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New Member

Connection to a RS232 serial device via IP

We have a 2600 Router with a 16-port Async Network Module installed in slot 1. (BTW, I can find no documentation on what turns on this line's little green status light).

What we are trying to do is add a basic RS-232 serial device in such a way as a client can telnet (or frankly open a socket connection) to communicate in ASCII text to the device.

Any Win95 laptop with a null-modem cable and Hyperterminal could normally communicate with it by typing instructions. We would like to have this functionality via an IP address.

I have followed the "How to Tunnel Async Data" instructions which seemed to clear much confusion about configuring a "line". Except, how do I give this line an IP address (and port)? The example uses a comm server instead of a router.

Also, I am really unclear on what an async interface is used for. Is an async interface relevant here?

Any pointers would be appreciated. Thank you for your time and effort.

Ed Chambers

Cisco Employee

Re: Connection to a RS232 serial device via IP

It sounds like you have 2600 with NM-16A module and wants to conect RS232 speaking device to one of the 16 port and PC's which are sitting on the LAN of that 2600 router wants to talk to that RS232 device over i right?

For that you just need to configure the "line" part. You don't need to configure any async interfaces. router will work as "comm server". Here is the place who discuss that.

Here the Router1 works as a "comm server" to get in to the RS232 speaking devices (routers) sitting at one of the 16 different ports.

OR clarify the network setup more..thanks..Tejal

New Member

Re: Connection to a RS232 serial device via IP

Thanks! That is exactly my configuration. I performed the setup and can now telnet to the line.

However I do not get any of the data I know the device is producing once per second. I suspect a cabling problem. The green LED on the back panel is not lighting for this line. Is that bad? What causes it to light?

Lastly, are there any debug switches to turn on to verify the router is receiving data from a line(whether or not I correctly telneted to it)? All lines claim they are Ready in a show line command.

New Member

Re: Connection to a RS232 serial device via IP

I sucessfully opened a telnet setting and established two-way ASCII communications. The transmit and receive lines in our setup were crossed (in addition to everything else). The little green status lights never did come one, but I'm not going to worry about it.