goldstein%delni.DEC@decwrl.dec.com (Fred R. Goldstein dtn226-7388) (11/07/88)
desnoyer@Apple.COM (Peter Desnoyers) writes, >Subject: Re: Voice Money >Date: 2 Nov 88 17:25:37 GMT >I am trying to find an answer to the following question - neither >AT&T's Q.931 spec nor an ANSI draft I have give any helpful >information. > >How do you do keypad terminal to terminal signalling in ISDN? In other >words, what happens when you press a key on a voice-only ISDN phone >during an active call? In ISDN, the human interface (things like buttons on the phone) is not standardized; the electrical interface (line and signaling protocols) is standardized. Thus "key" is simply an artifact. And a mighty handy way to tell the cpu in your telephone set what you want to do. There are two ways a call can be initiated in DSS1/Q.931. En-bloc sending means the call is initiated by a SETUP message with all of the digits included in the called party number information element. Overlap sending means you don't have any/enough digits in the SETUP, so subsequent INFO messages carry the keypad digits, until they're all done. En-bloc sending is more efficient for machine dialing; overlap is mainly for plain olde telephony. These are all out-of-band messages, on the D channel. NO tones are every sent. Now if you want to send tones down the line, you have to think of them as more like modem tones than as dialing tones. Again two options theoretically exist. You phone can generate them (internal modem, for convenience -- touch-tone generators are cheap enough to make this viable, though it's certainly not required by ISDN), or if your phone company sees a market for it, they can offer a supplementary service by which they generate tones for you, in response to some keypad digits. I wouldn't count on the latter, though. The moral of the story: TOUCH-TONE IS OBSOLETE. Since ISDN does NOT use tones, applications shouldn't be built around it. Voice recognition is a lot more reasonable for commercial applications. You may find touch-tone generators in many ISDN installations, but they may not be as convenient as they are now. BTW there's also ISDN "User to User Signaling", a D-channel low-volume packet delivery service of sorts, which may in some cases supplant in-band tones. But it too may carry a fee. fred _________ These views are mine and not those of DEC, ANSI T1S1, CCITT, ITU, WATTC, ACLU, MSPCA, RSFSR, or anyone else, unless it's their choice, not mine.
ron@ron.rutgers.edu (Ron Natalie) (11/10/88)
I wouldn't go so far as to say they are obsolete. Since ISDN is still in the nebulous phase, TouchTone service is what we have. Even my cellular car phone, which doesn't use TouchTones for dialing either, generates tones when I push the buttons so I can play with voice mailboxes and such. -Ron
soley@vector.uucp (Norman S. Soley) (11/15/88)
In article <telecom-v08i0176m07@vector.UUCP>, ron@ron.rutgers.edu (Ron Natalie) writes: > I wouldn't go so far as to say they are obsolete. Since ISDN > is still in the nebulous phase, TouchTone service is what we have. > Even my cellular car phone, which doesn't use TouchTones for dialing > either, generates tones when I push the buttons so I can play with > voice mailboxes and such. Does your phone make them or are they generated by cellular dialer to DTMF converted somwhere at the interface between the celular net and the regular phone system? I know that's what gets done in some digital PBX's for exactly the same reasons you mention. -- Norman Soley - Data Communications Analyst - Ontario Ministry of the Environment UUCP: uunet!attcan!lsuc!ncrcan!ontenv!soley VOICE: +1 416 323 2623 OR: soley@ontenv.UUCP " Stay smart, go cool, be happy, it's the only way to get what you want"
chip@vector.uucp (Chip Rosenthal) (11/21/88)
In article <telecom-v08i0176m07@vector.UUCP> ron@ron.rutgers.edu (Ron Natalie) writes: >I wouldn't go so far as to say they are obsolete. Since ISDN >is still in the nebulous phase, TouchTone service is what we have. More specifically, I think the original author was saying that DTMF ("touch tones") will be obsolete in the subscriber loop. It is already obsolete through the long-haul network. Aside from the Coming ISDN Revolution(tm), there is an impetus to move towards totally-digital equipment throughout the network. The changeover is starting in the business sector, and is being driven by those who use digital PBX's rather than analog channel banks. -- Chip Rosenthal chip@vector.UUCP | Choke me in the shallow water Dallas Semiconductor 214-450-5337 | before I get too deep.