Extended Distinctive Ring (Edr) - ZyXEL Communications U-336S User Manual

Extended Distinctive Ring (EDR)

Extended Distinctive Ring (EDR) is a special feature designed for
single telephone line home use to receive fax or data calls without
interfering with regular voice calls. When most users install a fax/modem
at home, they won't subscribe to an extra telephone line for occasional
fax or data calls; however, fax/data calls do come in from time to time.
If a user lets the fax/data software application answer, voice calls will be
missed. On the other hand, if the user or an answering machine
answers, fax or data calls may either be missed or the person who
answers the call has to go through some procedure to get this call
connected to the proper application. Either way is not desirable.
Once enabled with the proper settings, EDR can:
1. Detect the data/fax CNG tone without physically answering the call.
After a CNG tone is detected, the modem will report RING or
RING n to the application software. The software can cause the
modem to answer the call.
2. Detect several DTMF tones without physically answering the call.
The DTMF tones, once detected by the modem, will be reported
as RING or RING n to the software application.
With these two functions, your modem can be installed with an
answering machine or voice telephone set at home. In most cases, the
modem should not be set to answer regular rings, nor to report them.
Thus, the software will not instruct the modem to answer the call when
the phone rings. When a call comes in, the answering machine will
answer the phone and play a voice message. At this moment, the
modem, having detected the ring signal is gone, will start to listen to the
line for CNG tone or DTMF tones.
If the remote caller is an unattended fax machine, it will send a CNG
tone for a period of time. The modem will detect the CNG tone and
Special Functions 59