BT Phone to PDA via 56k instead of GPRS?

[VT-Vincent]

I've been reading up on the topic of connecting to the internet via a BT-enabled cell phone and one thing I've seen seldom discussed is instead of using GPRS, using a standard 56k dialup account. If I'm not mistaken, when the BT phone is paired, it is seen as a modem, in which case it should be possible to supply it with 56k dial-up info. Is this possible, and if so, are there any drawbacks to this verses GPRS?

[GSmith]

This is called "CSD" (I forget what it stands for, maybe Circuit Switched Data). The big drawback is it is only about 9Kbits per second, compared to 40kbits with GPRS (and 120kbits with EDGE). I'm not sure the theoretical data rates, I'm just reported what I've experienced.

Basically, your provider must support this (I think they have modems at their central office that do the dialing into your ISP, similar to the way fax<->cellphone works), and the data is charged differently on your bill, depending on your provider. For years in the United States, my local provider (Powertel at the time, bought by VoiceStream, bought by T-Mobile) provided CSD at the same "voice minutes" rate. Now I use GPRS and EDGE unlimited data for $20 per month.

[VT-Vincent]

Hmm... did you mean KiloBYTES instead of KiloBITS? 56k service is typically around 7 Kilybytes per second, a speed of 9 Kilobits would equate to only a single kilobyte per second :(

[GSmith]

Nope, I meant 9 kiloBITS per second. And you are correct, it ends up being about 1kbyte per second or less.

If you use the GPRS/EDGE data capabilities of your cell phone and use the cell phone company as an ISP, then you will get higher data rates.

If you use your cell phone to dial your own (separate) ISP, then you are using CSD and this will be 9 kbits per second and be very slow. You cannot use a "56k modem" with a cell phone, and the "56K dialup account" refers to the ISP's modem. *YOUR* modem will only be able to do 9kbits/s because you would be using CSD. The voice encoding happens on your cell phone, then it sends the voice data to the cell company's tower. When you send data over CSD, it uses the same "voice data channel" to send the data, which happens to be about 9kbits/second. When you connect over GPRS, the cell phone sends data over multiple "voice data channels" to get a higher data rate. That's why GPRS is about 5 times faster than CSD, because it combines 4-5 voice data channels to send more data at a time.

I hope my writing is clear on this.

[VT-Vincent]

That makes a lot of sense, I can now see why dialup over BT is seldom discussed :(. I am curious if GPRS is an option in my case... I have Cingular and I have heard of many people using it for Internet access, but I have also heard that they have locked the service into WAP-only sites. I am also considering the idea of a Pocket PC Phone now.

[GSmith]

Cingular in the US (is that redundant?) has $20 unlimited GPRS/EDGE. I use and highly recommend it (as well as the T-Mobile GPRS).

You will want the MediaNet Unlimited. Make sure that you have the representative take off "PPU". This is also worth a call to customer service after the sale to verify that "PPU" is not on your account.

If you ask about "tethered" use (meaning connecting your cell phone to a PDA or laptop), they might try to sell you the $80 per month plan. Decline and get the $20 unlimited GPRS/EDGE. Some sales reps are mistaken in which plan you need.