Traditional Voice Connection Modem over CDMA digital Cellular?

December 29, 2005 12:15 AM

Can I do a modem data connection over voice-only CDMA digital cell phone? How about other data/SMS/email hacks?

I have Cricket cell service with unlimited minutes, unlimited US long distance, and unlimited incoming SMS and unlimited outgoing US SMS.

However, Cricket neither offers data service nor does it offer WAP web access.

I can call any number in the continental US. I'm open to suggestions for any ISP, especially if it's cheap or free. But it should offer a compliant TCP/IP and IP based connection of any sort.

Is it possible to do a POTS style modem connection over CDMA/triband digital voice? Or is it too compressed/filtered? Are there PCMCIA modems/protocols designed to deal with this bandwidth/frequency compression and filtering?

Is it possible to hardwire an RJ-11 or similar phone/audio connection to the headphone port for use with a PCMCIA or other modem, as though it were a landline?

(Trickle-slow data rates are better than nothing. My first modem was 75 baud, so I know how to still do many things like, say, telnet to my friends box from a proper ISP and browse with Lynx)

Part 2:

What SMS functions (besides AIM-to-SMS forwarding) can I play with? Are there any decent free webmail clients that forward to SMS? (Gmail, sadly, doesn't seem to offer this, and my Cricket SMS service doesn't offer a proper [e-mail] bridged email address)

What about IRC-to-SMS bridges? Other fun toys, alert services, and tools? (I'd love to get, say, NWS/NOAA weather alerts and forecasts.)

posted by loquacious to computers & internet (9 comments total)

1. Yep. You can typically get data rates of 9.6k-14.4k
You'll need a serial or usb cable for your phone. And make sure you have a good signal. I used to do this all the time.

2. You should be able to do it with google

one example of an irc to sms gateway

You can bridge just about anything to sms. Search google for whatever to sms gateway. Most of the fun stuff can actually be done via email and filters.
posted by zerokey at 3:40 AM on December 29, 2005

Yep. You can typically get data rates of 9.6k-14.4k
You'll need a serial or usb cable for your phone.

That's only if you were making real data calls. Analog modem calls can be done, at 2,400 bps max. I don't think setting it up is as simple hooking an RJ11 to the headphone port, though I can't tell you how.
posted by cillit bang at 5:15 AM on December 29, 2005

Yeah, data service isn't available *at all* which is goofy. I'd be perfectly happy with a capped bandwidth data service that used less bandwidth than a normal voice call.

I'm thinking of giving it a shot. There are people already making modular RJ-11 to headphone jack adapters for doing silly things like using a big-ass AT&T home phone handset as the, uh, "handsfree" accessory.

All a good modem needs is a solid audio connection - this is how acoustic couplers work. There's no sideband information or out of audio band signalling going on, but POTS is just - AFAIR - 300-600 hz. I have no idea what CDMA's audio frequency band allotment is, and I can't force the phone into analog only mode - I'm assuming that the CDMA audio frequency allotment and audio codec compression routines are going to be the bottleneck.

Also, Cricket doesn't seem to offer a [e-mail] or @mycricket.com SMS forwarding service. I know most other cell services routinely do offer this, but they generally charge customers per email/SMS. I've tried emailing test mesages to variations of my phone number combined with various cricket domains with no results - meanwhile SMS messages entered on their web app show up almost instantly.

So, they do offer a web messaging gateway which may be scriptable - but I wouldn't be surprised if they banned IPs for too much activity.

Cricket service isn't like other cell services, as they seem to focus on creating a limited service area based on one single access node or just a few nodes to cover a major metropolitan area - metropolitan areas that seem to be large and flat, or smaller and lower density. This is probably how they can offer unlimited voice calls for an attractive rate. A WAP or TCP/IP back end would probably add too many costs.
posted by loquacious at 5:50 AM on December 29, 2005

I think the magic phrase here is Circuit Switched Data, or CSD, which runs at 9.6kbps.

Don't know if you care, but since Cricket expressly forbids you from doing this in their TOS:
...the Service may only be used for voice communications and may not be used with automatic number dialers or to transmit or knowingly receive data not authorized by Cricket.

...Well, I doubt that they have CSD running. And since they're using BREW-'enabled' phones, I don't think that any on-phone data hardware is going to work.

You MIGHT be able to use some sort of acoustic-coupler style adaptor through the headphone/mic port of your phone and get 300-2400baud, but you'll be tying the phone up for long, long stretches of time (Packet data over 2400 baud is excruciatingly slow!), and chances are good that Cricket would probably drop you for it.

That said - I wasn't aware that Cricket was still in business. Other than your current problems, what do you think of the voice/SMS service/availability of the network in your area?
posted by Orb2069 at 6:58 AM on December 29, 2005

Heh, I guess I should read the actual TOS before kludge-hacking my phone and trying to force data through their network. Fucking Cricket. What the hell?

Yeah, 2400 is pretty slow. But I could still do shell account stuff with that - check email via PINE, do limited Lynx browsing and whatnot. Text only would be fine - I'm not looking to transfer any real files or anything.

I'm in Phoenix and the coverage area is pretty large. 20x20 miles? 30x30? It pretty much covers the entire metro area, save for a few of the outlying communities. The service is pretty solid. I have hardly any dropped calls. SMS messages are nearly instantaneous. For where I am and where I go on a day to day basis it's an excellent service - and with the unlimited long distance it's a fine landline replacement.

I called Cricket a moment ago and they confirmed that they don't offer a [phonenumber]@cricket.com service, it's pure SMS only. That leaves limited SMS service options.

Scripting their web-based SMS gateway would probably also violate their TOS. If they can do a web gateway for SMS, why the heck can't they simply pass on some emails?

I think I'm just going to have to consider biting the bullet and saving up my money for the heinous deposit that will be required for my poor credit and get a proper cell phone and service if I really want mobile data services. But I can't help but feel that Cricket is missing out by not offering an extended package that includes at least WAP and email-to-SMS, if not pure data connections.
posted by loquacious at 7:16 AM on December 29, 2005

It would be interesting to attempt in the interests of science, but I'd be surprised if you got usable results from this experiment. The vocoder used in cellphones will manhandle the audio signals generated by your modem and (I think) turn them into something unrecognizable at the other end. But if you try it, do report back!
posted by adamrice at 7:21 AM on December 29, 2005

I would be suprised if you could get two modems to negotiate any speed over an acoustic coupler on a cell phone. Even with a really loose VOIP codec I could barely keep a 14.4k connection going. Cell phones, be it CDMA or GSM, are a lot more lossy and restrictive than typical VOIP implementations.

This guy skipped the acoustic coupler option and just soldered the ins and outs on his phone to a modem. He was able to get 1200 baud. Oh man, that brings back memories. I hope you've mastered the unix command line.
posted by skallas at 7:50 AM on December 29, 2005

Hmmmm. It seems that some of the games that Cricket offers use the data backend of the phone, possibly walled off from Teh Intarweb, possibly not.

So, they've got some sort of data running - The next question is, of course, how to get your phone to let you have access to it.

The only way I can think of to do it is to reflash your current phone with Verizon software patched to work on your cricket account - Complicated, dangerous, and I don't know if it would work. Dig around on Howard Forums if you're interested.

If you're thinking of jumping ship, you might be interested in Cingular's PAYG service - It offers Data (Per KB) - The rates are bad, but not impossible. T-Mobile has good PAYG rates, but no data for PAYG customers aside from a very limited WAP portal (Which IS free, however.).

WRT other SMS services:

You might also try texting 'Help' to 92466 ('YAHOO'), and see if the yahoo gateway works for you.

Also, though you already know about the AIM serices, you may not know about the bots (AOLBuddy), (AOLYellowPages), (MovieFone) and (ShoppingBuddy) - AOLBuddy is the original, and probably most flexable of the bunch, offering weather, sports, movie times in your area, a dictionary, and a bunch of other swiss-army type data applications. Shopping does price reporting, and is pretty representative of the range available online.
posted by Orb2069 at 7:58 AM on December 29, 2005

You wanna know what sucks? posting while drunk. shh!

Having your own question show up as the first result in a Google search. Damn.
posted by loquacious at 2:35 AM on February 21, 2006