LanMoC is a program to monitor and control a 3-Com LAN Modem™. This is modelled on the 3-Com Desktop Manager for the LAN Modem, and uses some of their code.

(16/12/1): New version

Added recognition of multi-link status, IP number detection, and a !Help file

I have also uploaded the source archive for LanMoC, which you are free to use for your own purposes, subject to the Artistic License conditions. ? …

Since LanMoC can now determine the IP number assigned to the link, in principle it could contact, for example,, to update a dynamic dns entry. But would there be sufficient interest in such a feature? Would be a good choice, or would people rather use another site? Please send your comments with this form:

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[From the LanMoC !Help file]

This is free software, released under the terms of the "Artistic License":

LanMoC is an application for RISC OS. It allows the user to control a 3Com ISDN LAN Modem (it may also work with the dual 56k analogue version, but I have not tested this).

LanMoC has been developed in part from example code supplied by 3Com for their "Desktop Manager".


To provide a desktop interface to the 3Com ISDN LAN Modem (may also work with the 56k LAN Modem - but untested), in a similar way to 3Com's own "Desktop Manager".


Copy the application to a convenient location, and run it. An icon will appear on the iconbar. This icon has two virtual LEDs, one for each of the LAN Modem's channels, duplicating the real LEDs on the LAN Modem itself. Initially these will show red, but after at most ~10 s the program should pick up a status broadcast from the LAN Modem, and then they will change colour to reflect the current status.

If the LEDs stay red all the time there is a problem. Check that you have an up-to-date firmware image in the LAN Modem - the very early version did not have the status broadcast, I think. With no other network activity, you should still see the LAN Modem 'TX' LED blink every 10 seconds or so, as it sends the status packet.

Once the status has been received you may make a call, or close a call, using the iconbar menu. This menu is also available from the status window that is opened by left-clicking the LanMoC iconbar icon.

The status window shows information received from the LAN Modem status broadcasts. For each channel, this is the call type, direction, provider name and duration. Additionally, LanMoC queries the LAN Modem statistics page to determine current IP numbers.

If you run a Help application (e.g. Resources:$.Apps.!Help) you will see some of this same information whilst the pointer is over the iconbar icon.

You may click "Quit" from the menu to exit LanMoC.

How it Works

Binary format status packets are broadcast by UDP from the LAN Modem, over the local network. LanMoC listens for these on a UDP socket. They are parsed to determine the current status.

To connect or disconnect calls, the http interface to the LAN Modem is used. This is achieved with the Acorn HTTP and URL modules, which must be available for LanMoC to run.

To determine current IP numbers, the stats3.htm page is retrieved from the LAN Modem.

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