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Asterisk: installing a TDM400P

This card has the benefit that you can connect an analogue phone as an extension, and supports UK caller id in the main Asterisk source without any patches.

If you only have a X100P card, you can still connect an analogue phone, but not as an extension. By plugging it in with a splitter connector alongside the PBX to the main line, you can either pick up calls on the PBX, or on the analogue phone. This works, but isn’t great. If you have fax detection enabled, it will be immediately picked up by the PBX, so that it can analyse the signal, so this won’t work. But with fax disabled, you get a few short seconds of the analogue phone ringing before the PBX extensions start to ring. The TDM400P card will allow you to directly connect an analogue phone to the system, bypassing these problems.

It is also possible to get UK caller id to work on the X100P card (if you don’t need the analogue extensions), but you have to use an unsupported patch.

The TDM400P card is a pain to install. The X100P is very deceptive, as it is extremely forgiving and seems to work anywhere. The 400, however, requires PCI 2.2 support from your motherboard. Older machines are unlikely to have this, but you may get lucky. You also have to have a spare power cable to attach to the card. The external connectors for phone lines are RJ-45 (yes, network connectors), but US phone cables will plug into the centre of these connectors and will then work.

If you have installed the card and it doesn’t work, you can tell because the green connection lights on the back of the card will not light up, and it won’t be recognised by the driver system (assuming that you are using asterisk@home). The normal routine when changing cards is to run:

genzaptelconf -s -d

After doing this, you will want to re-edit /etc/zaptel.conf for country settings.

Depending on which route you take, you will need to edit the zaptel configuration files:


For the TDM400P, /etc/askerisk/zapata.conf (I still need to confirm that this really works):


For the X100P patch, you want instead in zapata.conf:


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