telnet to Cognex In-Sight 4001 camera

chris.annin at chris.annin at
Mon Feb 25 20:42:15 CET 2013

yes, ive connected successfully using hyperterminal after I login it asks for user and I type admin press enter then it ask for password and type password press enter and it all works fine. using python ive tried ending both with "\n" and "\r\n" im thoroughly confused   

On Monday, February 25, 2013 11:24:22 AM UTC-8, square.steve wrote:
> At the risk of stating the blindingly obvious, have you run a 'real' telnet session to see what  a successful conversation looks like? Might give you some useful pointers for your debug session.
> Steve
> Sent from a Galaxy far, far away....  
> -------- Original message --------
> From: chris... at 
> Date:  
> To: pytho... at 
> Subject: telnet to Cognex In-Sight 4001 camera 
> Hello,  ive been struggling with this for a couple weeks now and was hoping someone might be able to help.  I have an older Cognex camera that I need to communicate with via telnet.  I can get a response from the camera when I initiate a telnet session but I dont seem to get any response when I write the user name to the camera -  I havnt been able to get any response writing anything. Im using python 2.7 and windows xp.  here is the code:
> [code]
> >>>import sys
> >>>import telnetlib
> >>>HOST = ""
> >>>USER = "admin"
> >>>tn = telnetlib.Telnet(HOST)
> >>>tn.read_until("Login: ")
> "Welcome to In-Sight(R) 4001 Session 1\r\nUser:"
> >>>tn.write(USER + "\r\n")
> >>>tn.read_until("User: ")
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
>   File "C:\Python27\lib\", line 319,
>     return self.read_very_lazy()
>   File "C:\Python27\lib\", line 395,
>     raise EOFError, 'telnet connection closed'
> EOFError: telnet connection closed
> >>>
> [\code]
> if i do a read_all instead of read_until for user I just get "..." returned.  Im assuming tn.write command isnt working?  any help would be greatly appreciated.
> thank you
> Chris
> -- 

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