Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

tunnel rs232 through IP network

I have 2 sites that are connected by routers utilizing IP for communications. I have scanning devices that connect to an RS6000 locally via a rs232 null modem cable. I have been requested to place a scanning device at a remote site. I would like to some how tunnel this data through the router connections. I have used STUN in the past to connect SDLC devices between an AS400 and 5394, but could not figure out how to get an async serial port on my RS600 computer to connect to this scanner's Serial port. Is there a way to tunnel this data through?



  • Other Network Infrastructure Subjects
New Member

Re: tunnel rs232 through IP network

Hi Phil....

There are two similar ways depending on your hardware......

The cheap and easy way is to use the aux port on your router. connect the devices to the aux port on each side, and once you set the basic flow controll stuff etc, use the 'autocommand telnet X.X.X.X YYYY' command on the originating aux port to get it to connect to the far end aux port.

If you do a show line on the router, it will give you the line number for whatever interface you want to use. If its port 31, then the port number for tcp is 2031.

Alternatively, if you have one of the async/sync modules ( NM-8A/S ) in youy router, then you can configure these to async mode and use the same autocommand telnet instruction.

Once data is received on that interface, it will open a tcp connection to the far end you specified and spew the data out on that port..

Hope that helps


New Member

Re: tunnel rs232 through IP network

Thank You

I will test it today.

Cisco Employee

Re: tunnel rs232 through IP network

Here is the best link which explains "hot to tunnel async data over ip"

This widget could not be displayed.