TECHNICAL BULLETIN #184 - Rev 1.00 (8/1/96) ============================================================================== TITLE : Setting Up Silent Answer PRODUCT : PROCOMM PLUS 3.x and 2.x for Windows ============================================================================== Silent Answer is a modem technology that allows a modem to distinguish between different types of incoming calls. Silent Answer is similar to Adaptive Answer, but instead of determining if a call is data or fax, Silent Answer determines if a call is voice or fax. Silent Answer Plus will discriminate between voice, fax, or data. Silent Answer is currently an exclusive technology of Supra Corporation's SupraFAXmodemsTM. Silent Answer operates in the following manner: 1. A call comes in. 2. On the first ring signal, the modem partially picks up the line and listens (snoops) for fax CNG tones. On some external models, the OH light may turn on. This snoop cycle will last 2-3 seconds. 3. If no CNG tone is heard, the modem will hang up so it does not interfere with the next ring signal. 4. If a person or answering machine answers, the modem will again snoop for a CNG tone for 2-3 seconds. It will again hang up if no CNG tone is heard. Because the CNG tones cycle is 4-5 seconds, these 2-3 second snoop cycles may not detect the tone. 5. If the modem does not receive another ring, or if no CNG tone is heard 6 seconds after the last ring, a 6 second snoop session is started. 6. If CNG tones are detected, the modem will answer as a fax. When the modem answers, several RING's will be sent to the terminal screen so that the software will answer. 7. If Silent Answer Plus is in use, the modem will also listen for a calling tone (1300 Hz for 600ms on followed by 1700ms off). If the calling tone is detected, the modem will negotiate a data call. 8. If neither a CNG nor call tone is detected, the modem will do nothing and treat the call as a voice call. DETERMINING IF SILENT ANSWER IS SUPPORTED As mentioned earlier, Silent Answer is currently used in only SupraFAXmodemsTM. The command to determine if Silent Answer is supported in a Supra modem is ATI10. The results from the AT10 might look like the following. ============================================================================== 104,115,120,121,123,140,141,142,143,144,146,147,149,150,151,153,154,157,190 SupraFAXModem 288 101=Class 1 FAX 104=Class 2 FAX 115=V.17 14.4Kbps FAX 120=World Wide support 121=V.23 123=Blacklisting 140=V.32bis 14.4Kbps data 141=SilentAnswer 142=CallerID 143=MNP10 144=MNP10/Cellular 146=AT\S config display 147=V.FC 28.8Kbps data 149=V.FC 24.0Kbps data 150=Enhanced &F options 151=Enhanced rate control 153=V.34 28.8Kbps data 154=SilentAnswer Plus 157=RINGING response code 190=FLASH memory ============================================================================== Some older Supra modems will only report the feature number, so notice that Silent Answer is feature 141 and Silent Answer Plus is feature 154. SETTING UP SILENT ANSWER Silent Answer needs to be set up differently depending on whether you are using Silent Answer or Silent Answer Plus. The following examples will assume the use of fax Class 1. There are two possible modes in which Silent Answer can operate. The first mode enables both Silent Answer and Adaptive Answer. This mode is activated by sending AT+FAE=2 to the modem. The Supra manual states that Silent Answer takes precedence over Adaptive Answer. In light of that, there seems to be no benefit to enabling both Silent Answer and Adaptive Answer at the same time. The second mode enables Silent Answer only. This mode is activated by sending AT+FAE=3 to the modem. A slight variation of this mode is called Silent Answer Plus. This mode is activated by the command AT+FAE=4. In terms of setting up PROCOMM PLUS for Windows 2.11 to use Silent Answer, there are two options. The first is to use "normal" Silent Answer (+FAE=2 or +FAE=3). This set up requires you to add a +FAE=2 or +FAE=3 to your data initialization string. SETUP FOR FAX CLASS 1 SILENT ANSWER After making the change to the data string, you then need to set your Auto- Answer Options to Fax. Set the Rings to Answer field to 3 to 5 rings more than what you or your answering machine will answer on. The second option is to use Silent Answer Plus (+FAE=4). Using this mode requires you to change your Adaptive Answer Command in Fax Connection. Simply change AT+FAE=1^M to AT+FAE=4^M. SETUP FOR FAX CLASS 1 SILENT ANSWER PLUS After making the change to the adaptive answer command, you need to set your Auto-Answer Options to Data and Fax. Set the Rings to Answer field to 3 or 5 rings more than what you or your answering machine will answer on. Now you need to set up the answering machine. This setup is the same whether you are using Silent Answer or Silent Answer Plus. The set up simply requires you to record an Out Going Message (OGM) with at least three seconds of silence before the actual message. Three seconds is simply a good starting point. If you have trouble, you may need to increase the amount of silence on the OGM. In order to use Silent Answer, your answering machine must be the type that automatically stops when an extension is picked up. If your answering machine keeps playing when you pick up the phone, you will need to purchase a device that stops it. Radio Shack sells a device called a Teleprotector (P/N 43-107) that will do this. PROBLEMS WITH SILENT ANSWER Use the list under About Silent Answer to try to determine where the problem occurs. You may need to extend the length of silence on the OGM if the tones are never being detected. If you have trouble with sporadic performance, try switching the fax class to Class 2 in Fax Connection. You need to be sure to change the Silent Answer Commands in Fax Connection or in the data initialization strings when you do this. If you are using Silent Answer, change the +FAE= in the data initialization string to +FAA=. If you are using Silent Answer Plus, Change the Class 2 Adaptive Answer command to AT+FAA=4^M in Fax Connection. To quote the Supra manual: "Silent Answer is relatively new, state-of-the-art technology; some people find that they need to experiment before Silent Answer works well for them." ========================================================================== To ensure that you have the latest version of this document, compare its revision number to that of the same document on any of our support sites. This technical bulletin may be copied and distributed freely as long as it is distributed in its entirety and it is not distributed for profit. Copyright (c) 1996 Quarterdeck All rights reserved. ==========================================================================