Switching to VoIP

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Chapter 12: PSTN Trunks

Project 12.5. Use Distinctive Ring Detection

What you need for this project:

• Asterisk with verbose logging enabled

• A POTS or Centrex line connected and working

• Two or more soft or hard SIP phones

Distinctive ring is a feature offered by some phone companies that permits you to use

two or three phone numbers with the same POTS line. Depending on which number

was dialed, the ring signal will differ, causing the ring to sound unique for each num-

ber. This feature allows parents to avoid answering their teenagers’ incoming calls.

With a fax/voice ring switch device, distinctive ring can be used to inexpensively use

a single line for receiving both fax and voice calls.

Distinctive ringing is a legacy signaling solution. That is, it works only

with POTS. On VoIP trunks, such functionality would be handled by

out-of-band signaling.

With Asterisk, distinctive ring can be used to automatically route calls from the

PSTN trunk to the right phones. Or the distinctive ring can just be passed through to

the phones on the private network, so that incoming PSTN calls cause them to ring

distinctively, too.

Each Zaptel channel can be configured to detect up to four different distinctive sig-

nals. The first thing we’ll need to do is open zapata.conf and add this configuration ...