RS232 Device outpout to file instead of printer

[Romain]

Helo there,

I have a mesure device with an outpout to a printer with RS232 cable.
It is in fact a Seiko DPU-411 thermal printer.
I would like to capture this data with a Terminal software on my
computer.
When I connect to RS232 cable to COM1 port I do not get anything on the
terminal.
I have tried with a spy cable, with the printer connected and the spy
connector on com1,
that way I can get the data.
But now I would like to get this data without having to connect the
pinter.
The thing is that i do not know the printer handshaking process.

I anyone could explain me how to get this data to a file without having
to have the printer connected it would be great.

Thanks a lot,

Romain

 

[Bennett Price]

I assume a spy cable is a "Y" tap. What happens if you use the spy
cable but don't have the printer connected or turned on?

There are two different handshaking or flow control protocols.

One is software and usually referred to as X-on/Xoff - the printer and
computer sends these back and forth in the data stream;
(X= Transmission).

The other is hardware RTS/CTS (request to send/clear to send) and is
implemented by raising or lowering the voltage on various pins. There
also may be other signals being used (DSR/DTR dataset ready/data
terminal ready).

Further complicating things is that you have two computers trying to
talk to one another, rather than a computer trying to talk to a printer
or a modem. For 2 PCS to talk to one another, you typically need a
'null modem' cable.

This site may help you a good deal

http://www.camiresearch.com/Data_Com_Basics/RS232_standard.html