> >>> 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.
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