evanc@isishq.fidonet.org (Evan Champion) (05/12/91)
I was curious to know if it is possible to set up a modem on a cellular phone (in the same fashion as a normal phone line). Would I need any special cabling, etc.? Thanks.
root@zswamp.uucp (Geoffrey Welsh) (05/13/91)
In a letter to All, Evan Champion (evanc@isishq.fidonet.org ) wrote: >I was curious to know if it is possible to set up a modem on >a cellular phone (in the same fashion as a normal phone line). >Would I need any special cabling, etc.? Thanks. Well, clobber Doug Thompson; when I in Ottawa last September, we planned to plug a TrailBlazer into my cellular phone to see how well it worked without any special preparations. We never got around to it. -- Geoffrey Welsh - Operator, Izot's Swamp BBS (FidoNet 1:221/171) root@zswamp.uucp or ..uunet!watmath!xenitec!zswamp!root 602-66 Mooregate Crescent, Kitchener, ON, N2M 5E6 Canada (519)741-9553 "He who claims to know everything can't possibly know much" -me
brian@telebit.com (Brian Lloyd) (05/14/91)
You will need a device that provides an RJ-11 connection for your modem. There are such devices available (I have used a device called Cell Jack). This device generates the signals expected by the modem (dial tone, ring voltage) and it decodes the touchtones so that the modem or other attached device can dial the cellular transceiver. You will probably want to try the Cellblazer in leu of a Trailblazer. The Cellblazer uses a version of PEP that has been optimized for cellular operation. It is also fully backward compatible with the TB+, the T2500, and the T1000. -- Brian Lloyd, WB6RQN Telebit Corporation Network Systems Architect 1315 Chesapeake Terrace brian@napa.telebit.com Sunnyvale, CA 94089-1100 voice (408) 745-3103 FAX (408) 734-3333
tnixon@hayes.uucp (05/14/91)
In article <0JPu22w163w@isishq.fidonet.org>, evanc@isishq.fidonet.org (Evan Champion) writes: > I was curious to know if it is possible to set up a modem on a cellular > phone (in the same fashion as a normal phone line). Would I need any > special cabling, etc.? Thanks. Yes, it is possible to hook a standard modem up to a cellular phone. A V.22bis modem works pretty well if you're stationary, but an echo cancelling modem (like V.32) will have problems. Of course, it's advisable to use error control. CCITT Study Group XVII is currently studying the issue of data transmission on analog cellular networks, including the possibility of standardizing special modulation schemes and/or forward error correction to improve block error rates, but many participants believe that such extraordinary measures are not necessary. You do need a special interface to the phone. These are sold by several companies, under license from a company called Tellular. The Tellular box provides a standard RJ-11 modular connector into which you plug the modem. Other than this, the only thing you need to worry about is providing power; you're probably best served by getting a modem that runs off batteries, although some are now available that will run off a plug in the cigarette lighter. Of course, an internal modem inside your laptop would work fine, too. -- 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
omahony@swift.cs.tcd.ie (05/16/91)
In article <0JPu22w163w@isishq.fidonet.org>, evanc@isishq.fidonet.org (Evan Champion) writes: > I was curious to know if it is possible to set up a modem on a cellular > phone (in the same fashion as a normal phone line). Would I need any > special cabling, etc.? Thanks. A study was done by the Irish PTT on it's Cellphone network to determine how good the network was for carrying data. Among their findings were the following: 1. They needed an adaptor to go from a two-wire PSTN modem to the essentially four-wire operation of the cellphone's transceiver 2. V.32 operation at 9600 and 4800 proved impossible - in 95% of tests, the modems failed to negotiate 3. V22bis (2400) was better, but could not sustain a reliable service 4. V.22 (1200 bps) with MNP4 and MNP5 proved satisfactory with average throughputs of 945bps to 1442bps respectively. These were approx 60-65% of PSTN throughputs. 5. All the above tests were for stationary operation. When the tests were carried out on the move, the throughputs went down to 51% of normal PSTN throughput. Although this is specific to the Irish CellNet, it may be of general interest. Donal O'Mahony omahony@cs.tcd.ie Computer Science Dept Trinity College Dublin 2 Ireland
keating@motcid.UUCP (Edward Keating) (05/20/91)
In article <1991May14.080415.28245@telebit.com>, brian@telebit.com (Brian Lloyd) writes: > You will need a device that provides an RJ-11 connection for your > modem. There are such devices available (I have used a device called > Cell Jack). This device generates the signals expected by the modem > (dial tone, ring voltage) and it decodes the touchtones so that the > modem or other attached device can dial the cellular transceiver. On Motorola products there is an option call the "Cellular Connection" which adds the RJ-11 jack and capability to interface to modems, etc. Back in June 1988, I used a USR HST 9600 to dial via a Cellular Connection through a LD trunk to Chicago from Peoria. I had the opportunity to examine the signal on a station analyzer that was connected to the antenna of the cell site. (I was at the switch site that had a co-located cell.) The 9600bps signal stayed within the bandwidth of the channel and I made the connection into our network in Chicago. After about 30 minutes of operation, the link disconnected with too many link errors. I attempted to reconnect, but it took several tries to get the link back at full speed. I dropped back to 2400bps which worked fine and had no problems. We did check out the signal at 2400 and found that it was a bit hotter than the 9600 and was pushing its bandwidth past the maximum allowed. (We did not see any adjacent channel problems.)