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-- why cant wire modems work with cell phones? (http://discussion.visorcentral.com/vcforum/showthread.php?threadid=12698)

I'm sure this is a stupid question to many of you, but I can't be the only one wondering...

If a modem can communicate data over a phone line with tones and screeching, why can't it use the same tones and screeching with a cellular phone.

Based on what I have read, you cannot make a cable that plugs into the hands free socket in a phone on one end, and plugs into the phone jack of my visor modem on the other.

I have been looking into completing my "bat belt" with one of those annoying cell phones. A local company is offering $30/mo service with unlimited local calling and no contract. It uses some digital technology called CDMA and only offers a Nokia phone without a built in modem or IR port. To get a phone with widely used visor syncing capabilities I seem to be looking at $40+/mo and lots of per-min calling limits and charges.

I just can't see why this is so complicated. Is the audio signal coming from the phone so poor that the modem can't make sense of it? Why would I need a phone that has a built in data modem if there is already a modem in my visor? Why are phone companies tied into using only specific phones if there are other phones on the market which offer the same technology? I would gladly pay retail for a phone that offers a visor-compatible cable and the same technology as the no-contract/no-limit service if that service would allow it.

Thank you in advance to anyone who can clear these questions up for me.

Jeff

You can find some answers to the question "why cant wire modems work with cell phones?" on this page: http://www.cellular.co.za/gsm_data-...se-analogue.htm

It relates to digital GSM cell phones, but I assume some of it must be true for any cellular network.

Other pages on this site also have good information on how data-over-GSM works.

HTH