> >>> Nice, I'm very glad to hear it works so well. I guess > >>> something like that would work even over an analog connection. > >> > >> On a true analog (800MHz AMPS service) cell phone, I've had > >> pretty decent success using MNP5 modems up to about 2400 baud. > >> The standard CCITT error dectection/correction schemes used on > >> landline modems isn't resilient enough for RF links. Good luck > >> finding MNP5 analog modems. ;) Multitech in St. Paul was the > >> last vendor I knew about that sold them, and that was 10+ > >> years ago. > >> > >> If you're talking about an analog connection to a digital > >> phone, it just won't work. The Codecs that digital phones use > >> are optimized for human speech and won't pass QPSK (or even > >> FSK) modem signals in a usable manner. > > > > What I meant there was that I should be able to dial up in > > this manner even if the signal is reported to be analog > > instead of digital. Is that true? > > I still don't understand what you're asking. Unless you're > 800MHz AMPS service, it's all digital. There is no analog > signalling on the network. > > If you're using an 800MHz AMPS service, then the "voice" > channel is an analog FM link band-limited to 300-3KHz with C > message weighting (just like a landline phone connection). You > can push an analog modem signal through that voice channel, but > the channel quality varies a lot and you need a really > bullet-proof error-correction scheme like MNP5.
What I'm trying to determine is, if AT&T or T-Mobile have the type of service you're describing: 1. will it work in both "analog" and "digital" service areas 2. does the phone need to support anything in particular to use it > > Are you saying it depends on whether or not the phone is > > capable of 800MHz AMPS service? > > I guess so. The carriers are going to shut down AMPS service > soon anyway. > > >> It's just passing on digital data that's carried by the > >> wireless protocol in use (GSM/TDMA or 1xRTT/CDMA). When you > >> "dial up a landline" with a digital cell phone, the wireless > >> carrier actually has to connect a modem to a landline at the > >> carriers switch and dial the number. The digital data from the > >> cellphone is then routed to that modem. > >> > >> If you're using the wireless carrier as the ISP, then there are > >> no modems involved at all: the digital data from the modem is > >> simply routed onto the Internet. > > > > I see. So the only ways you know of to get a laptop online > > with a cell phone are with a data plan in a digital service > > area, or with any Verizon plan in either an analog or digital > > service area? > > If you're using analog service, you can use any carrier that > allows normal phone calls to access a dial-up modem. You just > need a phone with a phone jack into which you can plug an > analog modem. Motorol "bag" style phones used to have a > accessor that plugged between the handset and the radio which > provided a modem jack. I don't think you're going to find too > many current phones that provide an analog modem jack. I don't think I'll have any luck finding a cell phone with an analog modem jack. Were you using an analog modem plugged into your cell phone with the service you were first describing? > Sprint also apparently has a free low-speed Internet access > service similar to Verizon's "QNC" service. I don't know if > Sprint's free low-speed service allows you dial up a > landline-modem or not. > > FWIW, I just plugged my VX4400 into my laptop, and Verizons > low-speed QNC service is still working. There are rumors > that Verizon is about to pull the plug on QNC, but those rumors > have been around for years. I've got to go with GSM. If both Sprint and Verizon offer it, there is probably a good chance that AT&T and/or T-Mobile do too. - Grant -- [EMAIL PROTECTED] mailing list
