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Note: Countries other than the U.S. may have different specifications for different ring
types. The manufacturer may append other sets of ring type specifications to suit each
country's needs.
10.5 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
absence of the ring signal, will start to listen to the line for CNG tone or DTMF tones.
Special Functions
U-90E Data/Fax Modem
10-9
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