djcl@uunet.uu.net> (08/08/90)
[The following was taken from IMEX's TELECOM echo area, which I started up for discussing Telephone/Telecommunications in the Toronto area - inquiries about IMEX or the TELECOM echo may be made to djcl@contact.uucp] From: Mark Foster Subj: Telephone diverters I recently purchased a ASAP TF 505 telephone diverter for under $200.00 this device allows for up t5 different devices to be hooked up to one incoming line. As an example you can hook up a FAX, Modem, answering machine, and two telephones to the diverter. When you call into the diverter it answers and gives the caller a false ringing, while its looks for a FAX CNG signal or a reverse modem detection (I have not tried these yet). If it detects these it then diverts the call to the modem or the fax. While it is giving the false ring, the caller (or computer) can enter up to a four digit access code and connect to one of two telephone output ports (the diverter actually regenerates a ring signal which will ring a standard 2500 tel set!!). Finally the fifth output port can have an answering machine which can give the caller instructions as to what is happening and how to enter access codes to get different connew3ctions to the five ports. In the final scenario the caller gets the beep from the t(answering machine and can leave a message. I have connected several phone to the ports and found the device to be quite acceptable. Note, if you pick up any device on any of the five ports, the rest of the ports are disabled. If anyone has one of these devices I would be interested in thier applications. Also I believe this device is available form Hello Direct under the trad name Autoswitcher. * Origin: The Super Continental (Opus 89:480/126)
dave%westmark@uunet.uu.net (Dave Levenson) (08/11/90)
In article <10671@accuvax.nwu.edu>, contact!djcl@uunet.uu.net (woody) writes: > I recently purchased a ASAP TF 505 telephone diverter for under > $200.00 this device allows for up t5 different devices to be hooked up > to one incoming line. As an example you can hook up a FAX, Modem, > answering machine, and two telephones to the diverter. When you call > into the diverter it answers and gives the caller a false ringing, > while its looks for a FAX CNG signal or a reverse modem detection (I > have not tried these yet). If it detects these it then diverts the > call to the modem or the fax. What in the world is "reverse modem detection"? The originating modem remains silent, expecting answer-tone from the answering modem? Does this box route silent callers to its modem port? Or does it only work with some non-standard modems that make noise while awaiting answer? As far as I know, some fax machines, in some originating modes, generate the CNG tone when they're awaiting answer. I know of no non-fax modems that would work with the device described above. Could somebody enlighten me? Dave Levenson Voice: 908 647 0900 Fax: 908 647 6857 Westmark, Inc. UUCP: {uunet | rutgers | att}!westmark!dave Warren, NJ, USA AT&T Mail: !westmark!dave
segal@uunet.uu.net> (08/13/90)
dave%westmark@uunet.uu.net (Dave Levenson) writes: >What in the world is "reverse modem detection"? The originating modem >remains silent, expecting answer-tone from the answering modem? Here is a guess ... The device is looking for V.25 calling tone. V.25 is the CCITT's version of a modem command set (like the "AT" set we all know and love), but it also includes a provision for calling tone similar to what Fax machines use. It is supposed to be used on all automaticly dialed calls by modems (i.e. whenever the equivalent of "ATD..." is sent). For those who want more details, V.25 describes the tone as a "1300 Hz or any tone corresponding to binary 1 of the DCE in use." It is on for 0.5 to 0.7 seconds, and then off for 1.5 to 2 seconds. Fax calling tone, on the other hand, is an 1100 Hz tone, on for 0.5 seconds and off for 3 seconds. >As far as I know, some fax machines, in some originating modes, >generate the CNG tone when they're awaiting answer. I know of no >non-fax modems that would work with the device described above. All fax machines are supposed to generate calling tone when the machine dials. If an autodialing fax machine doesn't generate calling tone (CNG), it is in violation of the T.30 recommendation for fax machines. Since there are some data modems that are V.25bis or V.25 compliant, there is a small chance that the "telephone diverter" in question is designed to use both Fax CNG and modem CNG as a means to route calls. However, the device in question would probably not work to well if it is looking for modem calling tone, as very few modems in the U.S. have the ability to generate it. Gary Segal ...!uunet!motcid!segal +1-708-632-2354 Motorola INC., 1501 W. Shure Drive, Arlington Heights IL, 60004 The opinions expressed above are those of the author, and do not consititue the opinions of Motorola INC.
AMillar@cup.portal.com (08/13/90)
dave%westmark@uunet.uu.net <10707@accuvax.nwu.edu>, Dave Levenson writes: >What in the world is "reverse modem detection"? In normal modem operation, the originating modem dials the phone and is silent until it sees a carrier presented by the answering modem. The answering modem detects a ring, goes off-hook, and sends a carrier to the originating modem. Then they go through their "connection" business to figure out if the other end is Bell 103 or 212A or whatever. An alternative mode of operation is available in my Micom-brand US$99 Hayes-clone modems. As part of the dialing command, there is a specifier to make the _originating_ modem produce a carrier after it dials, as if it were answering a call. The modem that is being called must pick up the phone as if it were making a call, and it will hear the carrier given by the calling modem. Reverse connections are no big deal in a manually-dialed call, because manual modems just have an originate/answer switch, and you flip it on both ends. In an automated Hayes-command environment, you have to change the way your software interacts with your modem. On my Micoms, the calling modem requires pause commas after the phone number in the "ATD" dialing command to wait for the call to go through. A letter "R" as the last part of the dialing string tells the modem to produce carrier instead of looking for it. On the answering end, I have not figured out any way to do auto-answering in originate mode with these modems. So, the software waits for the "RING" message from the modem, and then does a dial (ATD) command with no phone number. The answering modem thinks it is dialing a call, picks up the ringing phone line, and then detects the carrier produced by the calling modem. They do their "connect" thing and everybody is happy. There may be other modems that will auto-answer in originate mode, and mine may even do it (I just haven't bothered to pursue it). So ... Why would anybody want to do this? The first situation is the fax/modem switch-box, where the switch-box looks for modem carrier produced by the calling modem and transfers it to the answering modem. I use it for a modem on my company's PBX with Octel Aspen "automated attendant" call direction. There are no DID lines to people's desks at work. To reach an extension without going through a human operator, you call a main number that is answered by Aspen. You give it a touch-tone extension number, and it transfers you to that extension. The problem is that when the person picks up their phone, they get a message from Aspen saying "Transfer... Transfer..." and it takes fifteen seconds or so for you to get put through. It's no big deal on the voice side, but when you are a modem calling, and the answering modem picks up the line, it presents its carrier to the "Transfer..." message and by the time you get through, it's too late. With the reverse-originate setup, I can put in a delay which waits long enough for the real end-to-end connection before doing carrier. (You may ask why I didn't go for a direct-line to the outside. This way, the modem can be called from any internal extension and take advantage of tie-lines between sites. Besides, it's one less trunk to pay for... :-) The whole thing sounds like a pain, I know, but it takes longer to explain it than to set it up (as long as you can customize your software on each end). It works here! - Alan Millar AMillar@cup.portal.com
Dave Levenson <dave%westmark@uunet.uu.net> (08/13/90)
In article <10763@accuvax.nwu.edu>, motcid!segal@uunet.uu.net (Gary Segal) writes: > I wrote (in an earlier posting): > >What in the world is "reverse modem detection"? The originating modem > >remains silent, expecting answer-tone from the answering modem? and Gary responds, in part: > Here is a guess ... The device is looking for V.25 calling tone. V.25 and to my statement: > >As far as I know, some fax machines, in some originating modes, > >generate the CNG tone when they're awaiting answer. I know of no > >non-fax modems that would work with the device described above. Gary responds: > All fax machines are supposed to generate calling tone when the > machine dials. If an autodialing fax machine doesn't generate calling > tone (CNG), it is in violation of the T.30 recommendation for fax > machines. Our FAX machine (Brother 200) only generates CNG tones when it is in autodial mode. The trouble is, in autodial mode, if it gets a busy signal or a ring-no-answer, it just reports ERROR and drops the call. Therefore, I generally use it in manual-dial mode, where I can hear the call-progress tones from its speaker. I wait until I hear answer-tone from the far-end FAX machine, and then I press the START button. At that point, the speaker is cut off, and the machine sends CNG tones, followed by the actual data carrier. If I got a silent answer, I guess I'd have to assume its a diverter, and press the START button and hope... Doesn't sound very practical, does it? Dave Levenson Voice: 908 647 0900 Fax: 908 647 6857 Westmark, Inc. UUCP: {uunet | rutgers | att}!westmark!dave Warren, NJ, USA AT&T Mail: !westmark!dave