mcmahan@netcom.com (Dave Mc Mahan) (03/11/91)
I am involved in putting together a product for a medical application.
We are using a phone modem to transfer data from the home of a patient
to a diagnostic center where it can be processed. Most of our
patients are old and are do not understand the intricacies of the
modern phone system. The big problem we run into is that many
patients have Call-Waiting. As most of you know, this causes big
problems for a modem link. The application allows us to place a voice
call and then switch to modem data when it comes time to retrieve the
info.
My question is, "Is there any way to disable Call-Waiting AFTER a call
has been placed and a voice connection exists?". I'm looking for an
answer of "No way", or "Yes, and this is how you do it.".
Please e-mail your response to me directly.
Thank you for your knowledge in this matter.
Dave McMahan mcmahan@netcom.com
{apple,amdahl,claris}!netcom!mcmahan
[Moderator's Note: In many exchanges, the party wishing to suspend
call-waiting once a call is underway can do so by flashing, getting
new dial tone and dialing *70. They are then automatically returned to
the call in progress, with call-waiting turned off for the duration of
the call. Some of the exchanges which allown this suspension of
call-waiting after a call has started require that the phone be
equipped with three-way calling or some other valid reason for
flashing the switchhook in the middle of a call, other than merely to
cancel call-waiting. PAT]dave@westmark.westmark.com (Dave Levenson) (03/14/91)
In article <telecom11.197.3@eecs.nwu.edu>, mcmahan@netcom.com (Dave Mc Mahan) writes: > My question is, "Is there any way to disable Call-Waiting AFTER a call > has been placed and a voice connection exists?". I'm looking for an > answer of "No way", or "Yes, and this is how you do it.". In New Jersey, the subscriber must subscribe to the feature that allows disabling of call-waiting for this to work. This is a feature that may be ordered and priced separately from call waiting. If disable call waiting is purchased, then the subscriber may disable call waiting on an established call by flashing the switchhook, and dialing *70, and may then expect to be reconnected with the call that was in progress. Dave Levenson Internet: dave@westmark.com Westmark, Inc. UUCP: {uunet | rutgers | att}!westmark!dave Warren, NJ, USA AT&T Mail: !westmark!dave Voice: 908 647 0900 Fax: 908 647 6857 [Moderator's Note: Illinois Bell gives *70 for free. PAT]
stan@gatech.edu (Stan Brown) (03/17/91)
In article <telecom11.197.3@eecs.nwu.edu>, mcmahan@netcom.com (Dave Mc Mahan) writes: > My question is, "Is there any way to disable Call-Waiting AFTER a call > has been placed and a voice connection exists?". I'm looking for an > answer of "No way", or "Yes, and this is how you do it.". In reference to this question, has anyone been sucessful in making this work for outgoing calls placed by a Hayes compatible modem? What I don't know how to do here is get the modem to flash the switchook. Stan Brown P. c. Design 404-363-2303 Atlanta GA (emory|gatech|uunet) rsiatl!sdba!stan [Moderator's Note: On my US Robotics Courier 2400 modem, you use '!' to force the modem to flash the hook. But on outgoing calls, why wouldn't you just insert *70 on the front of the dialing string instead, as in ATDT *70-123-4567? If you want to flash the hook after the modem is already on the line, I guess you would get the modem's attention, with three plusses or whatever, followed by ATDT !*70 O, where the final letter 'O' means for the modem to go back on line. PAT]
tnixon@uunet.uu.net (Toby Nixon) (03/19/91)
In article <telecom11.212.4@eecs.nwu.edu>, the Moderator noted: > [Moderator's Note: On my US Robotics Courier 2400 modem, you use '!' > to force the modem to flash the hook. But on outgoing calls, why > wouldn't you just insert *70 on the front of the dialing string > instead, as in ATDT *70-123-4567? If you want to flash the hook after > the modem is already on the line, I guess you would get the modem's > attention, with three plusses or whatever, followed by ATDT !*70 O, > where the final letter 'O' means for the modem to go back on line. PAT] The "!" dial modifier also works with Hayes modems. You're right about prepending "*70," to the phone number, rather than trying to do it after the call is established. In fact, you CAN'T do it after the call is established, for two reasons: first, Hayes modems will give you an ERROR result code if you try to do an "A" or "D" command when you're already connected; second, if you DID hook-flash, you'd split the connection, which the other modem would see as a carrier loss which would cause it to hang up. The question has come up previously as to how to disable call waiting on INCOMING modem calls. I may have mentioned this here before, but it can be done fairly simply. You can't use Auto Answer (S0 > 0); your software must look for RING messages (or the RI lead to go high). Rather than issuing just an "ATA" command string to answer, use the string "ATH1D,!,*70,!;A". You might want to set S8=1, so the commas only cause a one second delay instead of the default of two seconds. Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net
scott@hsvaic.boeing.com (03/21/91)
In article <telecom11.197.3@eecs.nwu.edu>, mcmahan@netcom.com (Dave Mc >Mahan) writes: >> My question is, "Is there any way to disable Call-Waiting AFTER a call >> has been placed and a voice connection exists?". I'm looking for an > In reference to this question, has anyone been sucessful in making > this work for outgoing calls placed by a Hayes compatible modem? > [Moderator's Note: On my US Robotics Courier 2400 modem, you use '!' > to force the modem to flash the hook. .. > I guess you would get the modem's attention, with three plusses or > whatever, followed by ATDT !*70 O, where the final letter 'O' means > for the modem to go back on line. PAT] Unfortunately as soon as you switch the line over the modem on the other end would drop the connection. Modems need to be in continuous contact else they give up. That is why a call-waiting beep will usually knock you off line. Internet: scott@hsvaic.boeing.com UUCP:...!uunet!uw-beaver!bcsaic!hsvaic!scot [Moderator's Note: And also, even if you did keep your modem on line, when the phone line clicked out for a minute to allow your *70 input, the distant end would think carrier had been lost. You really can't win on this unless all modems everywhere were similarly adjusted. PAT]
ralphs@sumax.seattleu.edu (Ralph Sims) (03/22/91)
scott@hsvaic.boeing.com writes: >> [Moderator's Note: On my US Robotics Courier 2400 modem, you use '!' >> to force the modem to flash the hook. >> I guess you would get the modem's attention, with three plusses or >> whatever, followed by ATDT !*70 O, where the final letter 'O' means >> for the modem to go back on line. PAT] > Unfortunately as soon as you switch the line over the modem on the > other end would drop the connection. Modems need to be in continuous > contact else they give up. That is why a call-waiting beep will > usually knock you off line. > [Moderator's Note: And also, even if you did keep your modem on line, > when the phone line clicked out for a minute to allow your *70 input, > the distant end would think carrier had been lost. You really can't > win on this unless all modems everywhere were similarly adjusted. PAT] Right! S9=20 and S10=20 should keep the modems online even with a two-second drop in carrier. NOTE: the caveat is that BOTH modems need to be set up in this manner! Dragging the settings out a bit might be necessary to do the three +'s, etc. to get the modem back to command status. Ghads! This stuff can be a Black Art!
tnixon@uunet.uu.net (Toby Nixon) (03/26/91)
In article <telecom11.225.3@eecs.nwu.edu>, halcyon!ralphs@sumax. seattleu.edu (Ralph Sims) writes: > Right! S9=20 and S10=20 should keep the modems online even with a > two-second drop in carrier. NOTE: the caveat is that BOTH modems need > to be set up in this manner! Dragging the settings out a bit might be > necessary to do the three +'s, etc. to get the modem back to command > status. Ghads! This stuff can be a Black Art! You're right, it can be a black art -- more than you know. In fact, you don't quite understand S9 and S10 correctly! S9 specifies how long the carrier must be present (either initially, or on recovery after a dropout) before it is recognized by the modem. S10 specifies how long the modem can tolerate carrier to not be present before it hangs up. The measurement of S10 is dependent on S9 -- i.e., if the carrier goes away, it must come back for at least the time specified in S9 BEFORE S10 expires, or the modem hangs up. In your example, the modem wouldn't tolerate a two second dropout; in fact, it would ALWAYS HANG UP on ANY dropout. The maximum dropout which can be tolerated is the _difference_ between S9 and S10. If you want the modem to be able to tolerate a dropout of two seconds, you could, for example, set S9=6 and S10=26. Also, putting the modem into command state with a "+++" does NOT cause carrier to drop. When the modem is in online command state, it is still sending carrier (mark idle). So, there's no need to adjust S9/S10. But as I pointed out in an earlier post, there's no way to dial once carrier is present anyway, so the point is moot. Toby Nixon, Principal Engineer | Voice +1-404-840-9200 Telex 151243420 Hayes Microcomputer Products Inc. | Fax +1-404-447-0178 CIS 70271,404 P.O. Box 105203 | UUCP uunet!hayes!tnixon AT&T !tnixon Atlanta, Georgia 30348 USA | Internet hayes!tnixon@uunet.uu.net