Asterisk for analog pbx / small office - hardware questions

The device used for the pbx at my small office (nonprofit arts) died. The guys that provide me with tech assistance and advisement are all open source advocates and encouraged me to look into asterisk as opposed to the device I found that uses proprietary software on Windows to configure.

They’ll help with the network set-up and do the asterisk install and config. I’m not worried about that.

With some recommendations, it’s up to me to acquire the necessary hardware. I have queries re. fxo and fxs modules, hubs, and ATA vs SIP phones.

At this point we do not intend to go towards VoIP service, however we occasionally do projects that involve a flurry of international calls, so that may happen on a limited basis.

This is how we had mapped it out:
–2 phone company lines to asterisk via FXO modules in TDM400P card
–4 internal extensions needed; out by ethernet to hub or switch, then to 4 ATA devices, then to 4 analog phones

I prefer to use our old heavy-duty anolog phones. They’re good at surviving being dropped and banged about. The environment here is dirty, dusty, cluttered and chaotic.

My query re. fxo and fxs modules: if I get TDM400P card with two fxo modules and two fxs modules can I then forego two of the ATA devices and plug two analog phones directly to the TDM400P card?

If so, the two remaining lines would become part of our existing LAN. If not, we’ll set-up a separate LAN for the phone system. Of the four extensions, two get customary regular office use on a daily basis; the 3rd only gets used 5 to 30 times/month, primarily outgoing calls; the 4th is a stand-by, used only when large projects require an additional extension. Given this modest use, can I get by with a hub or do I need a switch for this network?

Finally, I was thinking of getting a couple cheapo phones like the Grandstream BudgeTone BT-102 instead of ATAs. Due to physical conditions here I’m not too enthusiastic about spending $75 to $200 apiece on phones. Any advice on that?

Not including the computer running asterisk, my budget for hardware and phones or ATAs is around $500.

Thanks in advance for any feedback!


I would look at the TDM842B that would give you 4 FXS and two FXO lines with 2 slots left over for future expansion. It runs about $600 but in my opinion a much better setup than the ATA’s hooked to ethernet.

Also, I agree with you - keep the analog phones in those nasty conditions. We do the same thing here (dusty, hot and humid factory floor) and the analog phones hold up well and only cost $20 to replace if necessary.

Thanks swaterhouse. That’s better than my half of this, half of that approach.


you could also look into a TDM400 with 4 FXS and then a TDM400 with 2 FXO… im thinking you can save a little cash there. unless your LAN is managed and supports QoS, I wouldnt put any IP phones or the asterisk server on it…