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From: fosler@inmet.UUCP
Newsgroups: comp.mail.uucp
Subject: Re: Help with uucp startup protocol
Message-ID: <125300001@inmet>
Date: Tue, 7-Jul-87 20:16:00 EDT
Article-I.D.: inmet.125300001
Posted: Tue Jul  7 20:16:00 1987
Date-Received: Sat, 11-Jul-87 17:54:17 EDT
References: <109@xyzzy.UUCP>
Lines: 44
Nf-ID: #R:xyzzy.UUCP:-10900:inmet:125300001:000:1753
Nf-From: inmet.UUCP!fosler    Jul  7 20:16:00 1987


     Once you have gotten thru the handshake, the INIT messages are 
asynchronous, so it possible for both master and slave to send the
first INIT message at the same time.  It just that both have to wait
for the INITA message before they can send the INITB and so on.
The following are the messages I get when talking to a ATT 3B2 system.

who          message         control byte values
send $10 $09 $71 $aa $39 $eb     0,7,1
get  $10 $09 $6f $2a $3b $77     0,7,3
get  $10 $09 $79 $aa $31 $6b     0,6,1
send $10 $09 $79 $2a $31 $eb     0,6,1
get  $10 $09 $7f $2a $2b $77     0,5,3
send $10 $09 $81 $aa $29 $0b     0,5,1

    The message format is
		byte 0 - synch byte always $10
                byte 1 - buffer size, with protocol g, its either 2 or 9 (control)
                bytes 2 and 3 - are checksum
                byte 4 - control byte
                byte 5 - xor of bytes 1,2,3,4

     The format of the control byte is
                bits 0 and 1 - packet type, 0 - CTRL, 2 - LNGDAT, 3 - SHTDAT
                bits 2, 3 and 4 - for CTRL packets, the type of CTRL packet
                             1 - CLOSE
                             2 - RJ
                             3 - SRJ
                             4 - RR
                             5 - INITC
                             6 - INITB
                             7 - INITA
                bits 5, 6 and 7 - for INIT type, size of INIT, for RJ, SRJ and
                                  RR, seqnum of message.

    So, the message you are getting is right (but not the checksums).  It is
a CTRL packet with a INITA, value of 3 (remember that the value is the last
three bits, not four).

Carl Fosler
Intermetrics, Inc.
Bethesda, MD.   301-657-3775.

fosler@inmet.inmet.com