Serial Over Modem

[Waterboy550]

I have a problem that I need solved. I have a remote serial device that communicates to a computer through hyper terminal. I would like to setup a connection as follows:

computer ---- modem ---- dial-up connection ---- device server with modem ---- serial devices

I have come across a few solutions on the web. Here is one that does what I need, but charges over $1,000 for a device server with built in modem that up to 8 serial devices can connect to.

Perle Device Server (sorry I can't post a link because I am a new member, you can just Google it).

I was wondering if anyone had any other solutions that can get the job done for a more reasonable cost. Thanks everyone.

 

[drozwood90]

What HA software do you use?

I'd suggest a custom piece of software on one side, then just a script or something on the other side. Just so long as you have the telco or a telco sim. in there somewhere.

--Dan

 

[sic0048]

I think the hard part is the fact that a dial up connection is not suppose to be permanent. So you would have to figure out how to handle the connection at the remote end of the line. I guess it is easy enough to have the computer answer a ringing phone line, but then you would have to have the serial connection try to re-establish itself as well.

I'm sure it can be done, but I think it is going to require some programming skills to make it happen.

 

[gatchel]

Make sure the call is not long distance...


You might be better using a dedicated Cable Modem or DSL line with a serial to ethernet converter like a Lantronix UDS1100 or something similar. Your PC would have a virtual comm port that communicates over IP to the serial server at the other end and then 232 or 422/485 to your device.

Please describe "remote" as I may be able to help more with a little more information.

Separate building miles away, or a house to a garage, etc....


edit: Holy crap, I almost forgot...

Blackbox makes a dedicated line modem that is capable of using a 4 wire dedicated line or a 2 wire dialup line. The modem actually stores the phone number to call and maintains the connection. They are pretty pricey though last I checked, you may be able to get them used with the way people are converting to IP these days.

Here:

Modem 3600

http://www.blackbox.com/resource/files/pro...ails/21542b.pdf

Confirm the specs first. I have never actually set on up on a dialup line but several on 4 wire leaded lines and I know the functionality exists, or at least did exist.

 

[twilo123]

yea i've actually looked at Perle systems also for remote serial connections (but not from dial up). they are definitely not cheap.

http://www.zoom.com/products/dial_up_external_serial.html

http://www.amazon.com/Modem-Blaster-DE5621...5765&sr=1-1

i've used these with radius for authentication but it was for dial up to network connection
http://www.wrca.net/mf/3com.html


virtual serial emulators won't work right
http://www.network-serial-port.com/
http://www.eltima.com/products/serial-over-ethernet/