ZyXEL Communications U-336R/RE Special Functions, Once enabled with the proper settings, EDR can

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 report RING to the software immediately. The software application can then issue commands to answer the call and receive the fax. If the remote caller is using a fax phone which does not send out a CNG tone and is waiting for a fax answer tone in order

48 Special Functions