On Aug 05, 1996 at 03:03 hrs, Ian Smith of 3:626/660 wrote to Brendan Short:

Hello Ian,

BS>> ! 07 Jul 23:05:42 MAX  Retry 493: Bad CRC at 3980928
BS>> + 07 Jul 23:05:50 MAX  CPS: 1137 (3989102 bytes)  Efficiency: 78%
BS>> = 07 Jul 23:05:50 MAX  UL-Z File\Uncheck\tyrian.arj

BS>> This happens all the time.. apart from the dropping
BS>> carrier.. Its really anoying..

 IS> Indeed.  It's a flow control problem, probably on the caller's end 
 IS> (if it only happens with one or two people), and/or on your end.  
 IS> Your caller's modem (or software, or both) is probably not set up 
 IS> properly for RTS/CTS handshaking, and so is streaming data at your 
 IS> system faster than it can take it in.

Why would this happen if the RECEIVING end were set up properly?  The usual
arrangement is to set the port to a speed higher than the highest incoming
data rate which means that if it sends it you can receive it.  

In this case the 1137cps receive rate indicates that the port is set to
19200 at least.  If this is the case flow control at the receiving end
shouldn't come into the picture.  

That puts the problem at the sending end.  I see two possibilities
depending on whether the sending end has flow control functioning or not.

1.  Sending end has flow control properly set up.  Noise injected into the
circuit BETWEEN the two modems would corrupt the received data causing the
receiving modem to ask the sending modem to resend the corrupted data.  If
this is what is happening then the sending modem is not handling the resend
requests properly.

2.  Non existant flow control at the sending end.  In this case the sending
end sends the entire file without stopping.  The sending modem buffer
overflows at some point and then it ignores any further data arriving from
the port.  When the buffer has emptied it stops transmitting and the
receiver program (BBS) eventually times out and says I have received up to
here (x bytes) please send the rest.  The above process continues until the
file is received.

Did I miss something?

Regards ... John
@EOT:

--- MsgedSQ/2 3.30