Using ordinary (digital) telephone sets

i have a snall setup of IP telephones on our SOHO local network using asterisk.

almost all PCs that we have contain internal fax/modem cards (and none are used!). all of these have software through which telephones could be used from the desktop (i.e. dialing, etc. by software; and telephone’s hand set for speaker and microphone).

i was just wondering if there could be some way to use the internal fax/modem card + ordinary phones as a cheap alternative to IP telephone sets.

any ideas? lead? hack?


why bother with that just use one of the many free softphones out there such as firefly. Or use one of digiums Wildcard TDM400p card and hook up 4 plain old cheap telephones

thanks for your reply. we have tried a few softphones. the general feedback is that people want to have a handset of sorts – something “real” that they are otherwise used to.

digiums Wildcard TDM400p cards are expensive. even single port card is five times the price of a fax/modem. of course, i don’t know if i could use palin old telephone sets using fax/modem cards on asterisk.


No, you definitely can’t. The best you can possibly hope for with a modem (and not just any modem, either) is to be able to use it to connect asterisk to a phone line - i.e., to the telephone exchange. You can’t possibly use it to connect a handset to. It would be like connecting two handsets together, they wouldn’t do anything.

willkemp, thanks for disappointing me :wink:

no, no. i am just kidding. thanks for your response.

i was hoping to see some hardware + software hack so that the plain old telephone sets could be used using some cheap interface card. the existing solutions (i.e. either IP telephones, or cards like TDM400p) are quite expensive.

may be the MAKE magazine guys should do something about it. is there anybody from MAKE on this forum?

Telephones require high-voltage (100V) to ring, and other things.
Your not likely to find a real cheap interface for them.

If you have lots of phones, the cost per port is less with a Channel
Bank and T1 card.

Otherwise there are lots of cheep SIP phones. The Zultys ZIP2
works great, and the Sipura 841 also works, but sound quality is sometimes
not as good as the Zultys.

In all small office the cost of a few $100 SIP phones is well worth
it compared to the agrevation of other routes to save only
a few bucks.