andrew@ramona.UUCP (Andrew Ernest) (09/28/88)
A couple of weeks ago I asked if anyone was having problems with S92=1. I received only a few responses (both indicating that they too were experiencing the problem). Since then I've been in contact with Telebit's tech support and I've come up with a theory for what is causing the problem. Unfortunately, Telebit cannot reproduce it. However, the person I've been dealing with wants me to survey everyone one more time, this time explaining my theory. Please send your results to me (uunet!ramona!andrew) and I'll mail a summary of them to Telebit. Thanks very much in advance to all who respond. Here goes. 1. Using cu or kermit or any other program that lets you send commands to your modem, issue the following command: AT &F This loads the factory defaults (don't worry, it won't wipe out what you have saved in EEPROM). If you weren't already talking to the modem at 9600 bps, you will have to reset your program's speed to 9600 so you can continue sending commands to the modem. 2. Once you've re-established the conversation with your modem, issue the command: AT M0 S92=1 This instructs the modem to cycle through the slow tones first when it answers a call. I also include M0 to disable the speaker...I experienced some feedback when the blazer was able to hear itself over the phone (in the next step). Thank goodness I stopped it before it got bad enough to cause damage. I would hate this to happen to someone else. Covering the mouth piece on the phone is another solution. 3. Using an ordinary phone, call your modem (don't exit your communications program). When the modem answers with the slow tones, hang up the phone. Wait until the modem hangs up. If the modem sends the string "NO CARRIER" after it hangs up, you will not be able to reproduce this problem. Skip to step #5 to reset your modem. If, however, your modem sends the string "BUSY", please proceed with the next step. 4. Call your modem again. The critical question is: does it answer with slow tones again *or* does it answer with *only* PEP tones? Please mail me this result (slow or PEP). If you hear only PEP tones, you are experiencing the problem I am having. 5. To reset the registers in your modem, issue the command: AT &E OK, my theory is that you can reproduce this problem only if your phone company sends a busy signal to your modem when it stays off hook too long after the calling party hangs up. I believe the blazer gets confused when it detects a busy signal while *answering* a call (rather than placing one, the more traditional environment for receiving a busy signal). This confusion is resulting in the modem answering all further calls with PEP tones only. At least that is what I've judged by observing the behavior of my modem. It is interesting to note that my modem will return to normal if, instead of hanging up when I call the modem, I hold on to the line and wait for the modem to hang up on *me*. This results in the string "NO CARRIER" (rather than "BUSY") and the modem will answer the next call properly (slow tones first). If *anyone* has any other ideas for what might be causing this problem, I would love to hear them. For now, I work around the problem by toggling DTR hourly to reset the modem. Telebit sent me a replacement modem but it exhibits the same behavior. Andrew Ernest (uunet!ramona!andrew)