492 lines
26 KiB
HTML
Executable File
492 lines
26 KiB
HTML
Executable File
<HTML>
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<HEAD>
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<TITLE>Bark file-request protocol extension.</TITLE>
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>
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<PRE>
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Document: FTS-0008
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Version: 003
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Date: 15-Oct-1990
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Updates: FTS-0001
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An Enhanced FidoNet(r) Technical Standard
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Extending FTS-0001 to include Bark requests
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October 15, 1990
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Status of this document:
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This document specifies an optional standard for the FidoNet community.
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Implementation of the protocols defined in this document is not mandatory,
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but all implementations of these protocols are expected to adhere to this
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standard. Distribution of this document is subject to the limitations of
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the copyright notice displayed below.
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Copyright 1989-90 by Philip L. Becker. Portions of this document are
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copyright 1986-90 by Randy Bush and are incorporated with his consent.
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All rights reserved. A right to distribute only without modification and
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only at no charge is granted. Under no circumstances is this document to
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be reproduced or distributed as part of or packaged with any product or
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other sales transaction for which any fee is charged. Any and all other
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reproduction or excerpting requires the explicit written consent of the
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copyright holders.
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A. Introduction
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1. This Document
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This document describes the standard for "Bark" type FidoNet file
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request operation. Bark file requests are an extension to the basic
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FTS-0001 mail session, and this document presents these requests as a
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modification to that document.
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2. What are File Requests?
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File Requests are a way of requesting that a specific file be sent during
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a FidoNet mail session. This has many advantages over simply logging on to
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a BBS and downloading a file:
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o You need not be a validated user
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o You don't have to spend time searching for the file on the BBS
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o You can schedule the file request to take place at any time without
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your being near your computer.
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There are two commonly used types of file requests on FidoNet today, WaZOO
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and Bark requests. WaZOO requests are used by Opus and BinkleyTerm, and
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are not documented here. See the document FTS-0006 by V. Perriello for a
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description of these. Bark requests were the first file request extension
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to the FTS-0001 protocol, and are supported (at least partially) by many
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mailers, including SEAdog, Dutchie, BinkleyTerm, and to a certain extent
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Opus. This document describes how to implement Bark-type file requests.
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B. Terms Used in this Document
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1. The diagrams and notations used in this document are the same as those used
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in the FTS-0001 document. Please see FTS-0001 for a description of these.
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This document should be considered as an extension to the FTS-0001 session
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layer protocol, and you will require FTS-0001 in addition to this document
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to fully understand what is presented here.
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In addition to the data description language described in FTS-0001 section
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A.4, one extra terminal used in this notation:
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(* terminals *)
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someName<max> - String of up to max chars, NOT null terminated
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C. Performing File Requests
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1. Introduction
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A Bark request consists of transmitting a special Bark Request packet which
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contains a filename, a date (used for update requests), and optionally a
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password. The system receiving the request then decides if it can send the
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requested file or not, and if it can does so using the same protocol used
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to send attached files. Bark request handling is always controlled by the
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answering system, and consists of two phases. In phase one, the receiving
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system asks the calling system to honor requests it may have to ask for
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files from the caller. In phase two, the receiving system allows the
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calling system to request files from it.
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Update file requests are the same as normal file requests, with one
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exception. If the date in the Bark Request packet (described below) is
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greater than or equal to the date of the actual file requested, the file
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will not be sent. The requestor should set the date to the date of the
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the actual file on its own end if an update request is desired.
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D. The Bark Request Packet
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1. Data Link Layer Data Definition.
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The Bark Request packet is a variable-sized packet containing a header, a
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filename, a date (which is used only for update requests - in a normal file
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request it's 0) and an optional password. When receiving a Bark Request
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packet, the ETX may be used to determine the end of the data portion. Note
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that the CRC is sent in the reverse byte order of a normal CRC XMODEM data
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block (see FTS-0001 section G.1).
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Note: some systems will send a password in the data block even if none is
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needed. Incoming passwords should be ignored unless the other system is
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trying to request a passworded file.
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Bark File Request Packet
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Offset
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dec hex
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.-----------------------------------------------.
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0 0 | ACK - Start of Bark Request - 06H |
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+-----------------------------------------------+
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1 1 | Filename - Packed DOS file format |
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+-----------------------------------------------+
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n n | SPACE - 20H |
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+-----------------------------------------------+
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n n | Date (0 if not Update Request) |
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+-----------------------------------------------+
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n n | SPACE - 20H (only if pswd follows) |
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+-----------------------------------------------+
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n n | Password (optional) |
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+-----------------------------------------------+
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n n | ETX - End of RESYNC packet - 03H |
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+-----------------------------------------------+
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n n | (*1) CRC low order byte |
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+-----------------------------------------------+
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n n | (*1) CRC high order byte |
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`-----------------------------------------------'
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*1 - CRC does not include the ACK or ETX and is
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in the reverse byte order from the CRC in a
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normal XMODEM data packet.
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2. Data Description Notation of Bark Request Packet
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DataBlock (no password) = ACK
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Filename<12>
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Space
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Date<11>
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ETX
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CRC
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DataBlock (with password) = ACK
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Filename<12>
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Space
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Date<11>
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Space
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Password<6|8>
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ETX
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CRC
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ACK = 06H (* Header for file request block *)
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Space = 20H (* Space character *)
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ETX = 03H (* End of block *)
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Filename (* Name of file requested *)
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Date (* ASCII string; the number of seconds
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since midnight, January 1, 1970 *)
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Password (* The password needed to request this
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file, if any. Maximum length is 6 for
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BinkleyTerm and Opus, 8 for SEAdog
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and Dutchie. *)
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CRC = crc[2] (* CCITT Cyclic Redundancy Check. The
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same algorithm as used for XModem
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CRCs. The CRC is calculated on
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all data in the block between but
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not including the ACK and the ETX *)
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E. Session Layer Protocol:
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This section describes the modified FTS-0001 session layer protocol. This
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is the only area of FTS-0001 which is modified to implement Bark style file
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requests. File Requests are performed at the end of the normal FidoNet
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mail session, after any mail pickup is performed.
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The diagrams below desribe the session level protocol with Bark file
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requests implemented. The state tables have been broken into subroutines
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but the FTS-0001 portion is not functionally changed. FTS-0001 sender
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states S4 through S7 are now table "Send Mail SM0". FTS-0001 receiver
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states R3 through R6 are now table "Receive Mail RM0". They are not
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functionally changed in any way from FTS-0001, they are just broken out
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to allow them to be used as subroutines. Finally Sender states S0 through
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S3 are unchanged, as are Receiver states R0 through R2.
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The remaining FTS-0001 states are enhanced to implement the Bark file
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request protocol. In addition, the subroutine state tables "Send Bark SB0"
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and "Receive Bark RB0" have been added to handle the actual file requests.
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The following diagrams fully replace the Session Layer protocol state
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tables in FTS-0001. No other changes to FTS-0001 are required to implement
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the Bark File request feature.
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Sender (Top level)
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.-----+----------+-------------------------+-------------------------+-----.
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|State| State | Predicate(s) | Action(s) | Next|
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| # | Name | | | St |
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+-----+----------+-------------------------+-------------------------+-----+
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| S0 | SendInit | | dial modem | S1 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| S1 | WaitCxD |1| carrier detected | delay 1-5 seconds | S2 |
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| | (*1) | | | Set SLO if > 2400bps, | |
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| | | | | Reset SLO if <= 2400bps | |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| busy, etc. | report no connection | exit|
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| | +-+-----------------------+-------------------------+-----+
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| | |3| voice | report no carrier | exit|
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| | +-+-----------------------+-------------------------+-----+
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| | |4| carrier not detected | report no connection | exit|
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| | | | within 60 seconds | | |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| S2 | WhackCRs |1| over 30 seconds | report no response <cr> | exit|
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| | +-+-----------------------+-------------------------+-----+
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| | |2| ?? <cr>s received | delay 1 sec | S3 |
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| | +-+-----------------------+-------------------------+-----+
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| | |3| <cr>s not received | send <cr> <sp> <cr> <sp>| S2 |
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| | | | | delay ??? secs | |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| S3 | WaitClear|1| no input for 0.5 secs | send TSYNCH = AEH | S4 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| over 60 seconds | hang up, report garbage | exit|
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| | | | and line not clear | | |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| S4 | SendMail | | (Send Mail SM0) | S5 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| S5 | TryPickup|1| Rcv TSYNC | (Receive Mail RM0) | S5 |
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| | (*2) +-+-----------------------+-------------------------+-----+
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| | |2| Rcv SYN | (Receive Bark Req RB0) | S5 |
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| | +-+-----------------------+-------------------------+-----+
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| | |3| Rcv ENQ | (Do Bark Requests SB0) | S5 |
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| | +-+-----------------------+-------------------------+-----+
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| | |4| Rcv 'C' or NAK | Send EOT | S5 |
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| | +-+-----------------------+-------------------------+-----+
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| | |5| Rcv Other Char | Send SUB | S5 |
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| | +-+-----------------------+-------------------------+-----+
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| | |6| No Data for 45 secs | Hang Up | exit|
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`-----+----------+-+-----------------------+-------------------------+-----'
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*1 - This state is shown for the extended SEAlink protocol. Omit the
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set/reset SLO actions if adding Bark to a strict FTS-0001 protocol
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implementation, or if not implementing overdrive in SEAdog.
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*2 - To refuse to pickup mail (S5.1) may send a CAN and stay in (S5).
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Note: Although the above shows the sender emitting only one TSYNCH, it is
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recommended that a timeout of 5-20 seconds should initiate another TSYNCH.
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The receiver should tolerate multiple TSYNCHs.
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Receiver (Top Level)
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The receiving FSM is given an external timer, the expiration of which
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will cause termination with a result of 'no calls' (R0.2).
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.-----+----------+-------------------------+-------------------------+-----.
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|State| State | Predicate(s) | Action(s) | Next|
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| # | Name | | | St |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| R0 | WaitCxD |1| carrier detected | | R1 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| external timer expires| report no calls | exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| R1 | WaitBaud |1| baud rate detected | send signon with <cr>s | R2 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| no detect in ?? secs | hang up, report no baud | exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| R2 | WaitTsync|1| TSYNCH received | ignore input not TSYNCH | R3 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| 60 seconds timeout | hang up, report not Fido| exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| R3 | RecMail | | (Receive Mail RM0) | R4 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| R4 | AllowPkup|1| Have pickup for sender| Send Tsync, | R5 |
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| | | | | Set T1=1 sec | |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| No pickup for sender | | R6 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| R5 | WtPickup |1| Rcv NAK or 'C' | (Send Mail SM0) | R6 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| Rcv SUB | Send Tsync, | R5 |
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| | | | | Set T1=1 sec | |
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| | +-+-----------------------+-------------------------+-----+
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| | |3| Rcv CAN | Report Mail Refused | R6 |
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| | +-+-----------------------+-------------------------+-----+
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| | |4| T1 expired | Send Tsync, | R5 |
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| | | | | Set T1=1 sec | |
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| | +-+-----------------------+-------------------------+-----+
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| | |5| 45 secs in R5 | Hang Up, report error | exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| R6 | AskBark |1| Wish to make requests | Send SYN | R7 |
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| | (*1) +-+-----------------------+-------------------------+-----+
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| | |2| No requests to make | | R8 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| R7 | DoRequest|1| Rcv CAN | Report Requests Refused | R8 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| Rcv ENQ | (Send Bark SB0) | R8 |
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| | +-+-----------------------+-------------------------+-----+
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| | |3| Rcv SUB | Send SYN | R7 |
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| | +-+-----------------------+-------------------------+-----+
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| | |4| Rcv NAK or 'C' | Send EOT | R6 |
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| | +-+-----------------------+-------------------------+-----+
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| | |5| Rcv Other | eat character | R7 |
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| | +-+-----------------------+-------------------------+-----+
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| | |6| 5 sec, no input | Send SYN | R7 |
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| | +-+-----------------------+-------------------------+-----+
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| | |7| 45 secs in R7 | | R8 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| R8 | WtPickup |1| Allow File Request | (Receive Bark RB0), | exit|
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| | | | | Hang Up | |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| Disallow Requests | Hang Up | exit|
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`-----+----------+-+-----------------------+-------------------------+-----'
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*1 - Some implementations always do (R6.1) even if they have no requests.
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Sender - Send Mail
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.-----+----------+-------------------------+-------------------------+-----.
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|State| State | Predicate(s) | Action(s) | Next|
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| # | Name | | | St |
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+-----+----------+-------------------------+-------------------------+-----+
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| SM0 | SendMail | | (XMODEM send packet XS0)| SM1 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| SM1 | CheckMail|1| XMODEM successful | (Fido registers success)| SM2 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| XMODEM fail or timeout| hang up, report mail bad| exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| SM2 | SendFiles| | (BATCH send files BS0) | SM3 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| SM3 | CheckFile|1| BATCH send successful | report success | exit|
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| | +-+-----------------------+-------------------------+-----+
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| | |2| BATCH send failed | hang up, rept files fail| exit|
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`-----+----------+-+-----------------------+-------------------------+-----'
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Sender - Send Bark
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.-----+----------+-------------------------+-------------------------+-----.
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|State| State | Predicate(s) | Action(s) | Next|
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| # | Name | | | St |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| SB0 | SendBark |1| File to request | Build Bark Request Pkt, | SB1 |
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| | | | | Set tries = 0 | |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| No more files to req | Send ETB | exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| SB1 | AskFile | | Send Bark Packet | SB2 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| SB2 | RcvFile |1| Rcv ACK | (Batch Receive BR0) | SB3 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| Tries > 5 | Send ETB, report failed | exit|
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| | +-+-----------------------+-------------------------+-----+
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| | |3| Rcv Other | Purge input, Incr tries | SB1 |
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| | +-+-----------------------+-------------------------+-----+
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| | |4| 10 sec w/o ACK | Incr tries | SB1 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| SB3 | NxtFile |1| Rcv ENQ | | SB0 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| Rcv Other | Purge Input | SB3 |
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| | +-+-----------------------+-------------------------+-----+
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| | |3| 5 sec, no input | Send SUB | SB3 |
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| | +-+-----------------------+-------------------------+-----+
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| | |4| 45 sec in SB3 | Hang up, report error | exit|
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`-----+----------+-+-----------------------+-------------------------+-----'
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Sender & Receiver - Receive Mail
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.-----+----------+-------------------------+-------------------------+-----.
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|State| State | Predicate(s) | Action(s) | Next|
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| # | Name | | | St |
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+-----+----------+-------------------------+-------------------------+-----+
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| RM0 | RecMail | | (XMODEM rec packet XR0) | RM1 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| RM1 | XRecEnd |1| XMODEM successful | delay 1 second | RM2 |
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| | | | | flush input | |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| XMODEM failed | hang up, rept mail fail | exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| RM2 | RecFiles | | (BATCH rec files BR0) | RM3 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| RM3 | ChkFiles |1| BATCH recv successful | delay 2 secs, rprt good | exit|
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| | +-+-----------------------+-------------------------+-----+
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| | |2| BATCH recv failed | hang up, report bad file| exit|
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`-----+----------+-+-----------------------+-------------------------+-----'
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Sender & Receiver - Receive Bark
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.-----+----------+-------------------------+-------------------------+-----.
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|State| State | Predicate(s) | Action(s) | Next|
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| # | Name | | | St |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| RB0 | HonorReq |1| Ok to honor request | Purge Input, Send ENQ, | RB1 |
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| | | | | Set T1 = 2 seconds | |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| Don't wish to honor | Send CAN | exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| RB1 | WaitBark |1| Got ACK | Rcv Bark Packet (*1) | RB2 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| Got ETB | Report done | exit|
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| | +-+-----------------------+-------------------------+-----+
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| | |3| Got ENQ | Send ETB | RB0 |
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| | +-+-----------------------+-------------------------+-----+
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| | |4| T1 expired | Purge Input, Send ENQ, | RB1 |
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| | | | | Set T1 = 2 seconds | |
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| | +-+-----------------------+-------------------------+-----+
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| | |5| 20 seconds in RB1 | Hang Up, Report error | exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| RB2 | AckBark |1| Bark Pkt Rcvd Good | Send ACK | RB3 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| Bark Pkt Rcv Error | Send NAK | RB1 |
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+-----+----------+-+-----------------------+-------------------------+-----+
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| RB3 | WaitStrt |1| Got 'C' or NAK | | RB4 |
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| | +-+-----------------------+-------------------------+-----+
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| | |2| No data for 3 seconds | Send ACK | RB3 |
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| | +-+-----------------------+-------------------------+-----+
|
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| | |3| 15 seconds in RB3 | Hang Up, Report Error | exit|
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+-----+----------+-+-----------------------+-------------------------+-----+
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| RB4 | SendFile |1| Can snd requested file| (Batch Send File BS0) | RB0 |
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| | (*2) +-+-----------------------+-------------------------+-----+
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| | |2| Can't send file | Send EOT | RB0 |
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`-----+----------+-+-----------------------+-------------------------+-----'
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*1 - If SUB (16H) received before ETX go to RB0 to resync bark receive
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*2 - While deciding if file exists, and if the password allows it to be
|
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sent etc., a NUL may be sent to buy 20 seconds more on the timeout
|
|
on the other end if it is using the SEAlink extended FTS-0001
|
|
specification protocol. Sending a NUL is harmless for a strict
|
|
FTS-0001 session, but will not buy more time.
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</PRE>
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