free software to encapsulate serial port traffic a la serial device server

[alpineranger]

I know you can buy little embedded devices to do this, but I'm wondering if it can be done with free software. Preferably the client end would be windows (as I want to interface it to proprietary software that might be windows only). The end goal is a networked home automation system.

 

[ScottMac]

What is your computer going to talk to?

There is some free stuff to talk binary through a Cisco terminal server (I think it's RFC 1722 .... something like that), but you have to have something on the other end of the deal to do/undo whatever your PC is talking to/at/with.

Good Luck

Scott

 

[alpineranger]

One of the things would be a computer controlled thermostat. Nothing that will require high bandwidth or low latency. I expect whatever I connect is going to come with whatever software I need and I don't want to worry about that. I'm sure they sell networked versions but I'm counting on being able to save money and add flexibility by transparently tunnelling the connection over a network.

random device <-serial-> pc#1 <-network-> pc#2 <application>
should look like
random device <-serial-> pc#2 <application>

 

[ScottMac]

That ain't gonna fly.

You need something to do the protocol conversion at both ends. If you had a thermostat (for example) with an Ethernet connection, it'd talk Ethernet, not serial.

If it only had a serial connection, then you'd need another device to do the serial->ethernet conversion.

That device is usually a terminal server of some sort (check out Lantronix, they have some 1 & 2 port models).

The bottom line is that you can't just dump serial protocols into an ethernet connection and get ethernet encapsulated RS232.

You *can* run serial protocols over UTP ... no problem, other than potential length limitations.

I made some microcontroller thingys to control the registers in my townhome to help balance the temp between the floors, and they talk to the main controller over UTP / RS232.

Whatever. You may want to investigate something like X-10 ... see SmartHome.com

Good Luck
Scott

 

[alpineranger]

I have a very thorough knowledge of ethernet (I'm a layer 2 software engineer for a large networking company) and I know exactly how and why just hooking wires from a serial port to an ethernet network won't work.

I've used devices that do what I want, but I can't afford them. Those lantronix devices you mentioned would work, I've personally used Digi hardware. You get a box with a bunch of serial ports and an ethernet connection, and on your pc you end up with a bunch of serial devices that look local (after installing the appropriate drivers). I figure I should be able to get the same procedure to work with the old pcs that I have.

Yes, I can run serial over UTP (I know about X-10 too), but this will not help me as I want to access the devices not just over the LAN, but over the internet several hundred miles away. I want to be able to monitor and set the temperature remotely from out of town.

Let me clarify:
serial device <-serial-> pc#1 running some software to encapsulate serial traffic over tcp or udp <-internet-> pc#2 running some software to unencapsulate the serial traffic <> program that expects to connect to said serial device on a local serial port