ZyXEL Elite 2864 User Guide - Page 145

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 calls, voice calls will be missed; on the other hand, if a human being or an answering machine answers calls, fax or data calls may either be missed or the person who answers a call has to go through some trouble 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, and the software can then request 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, a ZyXEL fax/modem can be installed with an answering machine or a voice telephone set at home. In most cases, the modem should be set to neither answer regular rings, nor report them. Thus, the software will not instruct the modem to answer the call when a 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 that the ring signal is gone, will start to listen to the line for a 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 to press the START button, the caller can press a designated DTMF tone, which will activate the modem to report and subsequently be ordered to answer the fax call. This is just one of the applications for which EDR can be used. We have designed many different ways to set the modem up to not only cover the basic usages, but also for different extended applications. Setting Up The EDR The new EDR can be used at home where multiple phones are installed in parallel. Once this function is enabled, the modem will go into EDR mode after the ring disappears, and it will be able to detect the data/fax CNG tone and DTMF tones, and report them as different types of rings. 13-7