Path: utzoo!telecom-request Date: Thu, 6 Jun 1991 19:34:40 GMT From: Greg Andrews Newsgroups: comp.dcom.telecom Subject: Re: Pet Peeve About Newer Modems (was Telephone Keypads) Message-ID: Organization: Netcom - Online Communication Services UNIX System 408 241-9760 Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 432, Message 4 of 7 Lines: 55 In article forrette@cory.berkeley.edu (Steve Forrette) writes: > This reminds me of a "pet peeve" (sic?) that I have with the newer > modems. Both the Hayes 9600 V-series and the $74 2400 card-modem I > have won't accept an ATS11 value (DTMF duration) of less than 50ms. > The default seems to be 100ms. The Hayes will take a smaller value, > but use 50 during tone generation. The clone returns ERROR for a > value less than 50. The old 1200 geniune Hayes that I have will take > values down to 1ms, and actually do it as well. Hmmm. You want your modem to use 36 ms instead of 50? So exactly how much time would you save with that extra 14 ms? I note that the S11 register controls the duration AND spacing of the tones, so every tone would be 14 ms faster and the space in between would be 14 ms faster. Seven digit numbers would be seven multiplied by the S11 setting, multiplied by two: 555-1212 = 7 x 50 ms x 2 = 0.7 seconds to dial the number 555-1212 = 7 x 36 ms x 2 = 0.5 seconds to dial the number A savings of 0.2 seconds Eleven digit numbers (ten digit with a leading 1 or 0): 1-408-555-1212 = 11 x 50 ms x 2 = 1.1 seconds to dial 1-408-555-1212 = 11 x 36 ms x 2 = 0.8 seconds to dial A savings of 0.3 seconds So for every eleven digits that the modem dials, the user can save 1/3 of a second if the modem uses 36 ms tones instead of 50 ms tones. How many switches in this country (and the world) can reliably handle DTMF tones faster than 50 ms? How many can handle them even that fast? Should modem manufacturers take steps to ensure their equipment works reliably with the broad range of switches out in the field, even at the expense of 0.2 - 0.3 seconds per call? Are modem users such speed demons that 0.3 seconds is begrudged? In my humble opinion, it's a little silly to get upset over such a small amount of time. Of course, I happen to work for Telebit technical support, so that may explain my viewpoint a little bit... Greg Andrews | UUCP: {apple,amdahl,claris}!netcom!gandrews | Internet: gandrews@netcom.COM