?? Modules for GPIB and Ethernet ??

[Roy Smith]

In article <21240387.0411050533.4d145e2a at posting.google.com>,
 justinhsia at yahoo.com (Chaser) wrote:

> I have an equipment that's controlled through ethernet.  (The control
> program is currently written in C++.)  I guess my really difficulty
> is, how do I send commmands to that devise through ethernet using
> Python?

You havn't given enough information to give a good answer, but I'll take 
a shot.

First, you need to know what kind of protocol your device talks.  It's 
virtually certain that the device implements some kind of custom 
application-level protocol on top of some standard transport layer such 
as TCP/IP.  Assuming that's the case, you need to:

1) Find the documentation for the application-level protocol it talks.

2) Find out the IP address (or hostname) of the device.

>From within Python, you will need to create a socket, connect the socket 
to your device using the connect() method, and then use the send() and 
recv() methods to talk to the device.  You'll need to implement the 
application-layer protocol yourself.

The details of how to use sockets in Python (i.e. connect(), send(), 
recv(), etc) are documented in "7.2 socket -- Low-level networking 
interface" of the Python Library Reference.  To really understand what 
section 7.2 is talking about, however, you need to have a general feel 
for how network communication works in general.  Fortunately, the 
introduction to section 7.2 contains some pointers to some good general 
reference books.