It sounds like you have most of the pieces. You're doing a LINE-ATT and
using GET and SEND to talk to the systech box. The device is sending you an
ENQ and you respond with an ACK that it doesn't recognize. So, 2 questions:
first, are you seeing the ENQ (and is there any associated data with the
ENQ?); second, what is the baud rate/parity of the systech, and where are
you setting it? If you are getting the ENQ and sending an ACK that's
unrecognized, maybe you've got the wrong parity.
Finally, it sounds like your POS is using tcp to talk to the systech, and
then you're using serial for the systech to talk to unidata. Would it be
possible to use tcp sockets and go directly from the POS to unidata without
the impediment of a serial link?

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Dana Baron
Sent: Tuesday, March 01, 2005 2:28 PM
To: [email protected]
Subject: RE: [U2] [UD] LINE.ATT for attaching serial line


George Gallen wrote:
> what is on the other side of the tty port? a modem or device? If a modem,
what
> is on the other end of the modem? Is this a PPP/SLIP or just system <->
> system.

This is part of an effort to interface with a Squirrel POS system. The tty
port connects to a Systech brand "serial port server". It's a box that sort
of converts serial to Ethernet. It has an IP address that is known by the
Squirrel server. Data going back and forth between the two systems is sent
over the network between the server and the serial port server. It's then
converted to/from serial. The interface protocol defines the structure and
content of the messages between machines. It's all based on serial
communications, with ASCII characters used to control the signaling (ENQ,
ACK, NAK, STX, ETX, etc).

Until now, I've been frustrated in my attempts to get the Squirrel system to
understand my ACK response to its ENQ. It usually figures it out after the
fourth or fifth try, but by then it's too late. Working with Squirrel
support, I learned that the buffer had data other than my ACK in it when it
arrived. I tried using the DELAY parameter on the LINE.ATT command and
suddenly Squirrel understood the ACK on the first try.

The Unidata manual says: "Warning On some platforms, you must specify DELAY
in LINE.ATT to avoid problems with subsequent UniBasic SEND commands
overlaying data". So, I guess I'm having problems with my SEND commands
overlaying data. Now I'd like more detail on what this means and how to get
around it.

(And to think, some people get to play around with UniObjects and other cool
things!)

Dana Baron
System Manager
Smugglers' Notch Resort
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