Forums > Specific Focus > Technical Mexico

alleygata

Feb 1, 2003, 8:05 PM

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Another Question About Cell Phones

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I have AT&T cell phone service, which I imagine will have to be changed once across the border, right? How is the cell service and the technology in Mexico? I want to buy one of the new phones that allows for faster internet connections when they come out. Should I expect to have to wait quite awhile for that technology to reach across the border or will it be available when it's available in the US?

Thanks!

Allie

Feb 1, 2003, 9:38 PM

Post #2 of 12 (2488 views)

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Re: [alleygata] Another Question About Cell Phones

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In Reply To

"Alleygata" writes:
I have AT&T cell phone service, which I imagine will have to be changed once across the border, right?

It depends on (a) what AT&T cellular service and phone you have and (b) what you mean by "changed once across the border".

Following the original analog deployment, AT&T opted for digital service using Time Division Multiple Access (TDMA) multiplexing on both the 850 ("cellular") and 1900 MHz ("PCS") frequency bands. A majority of their digital network is still TDMA. In the past approximately 9 months however, AT&T has also been selling phones which access their "3G" or "Next Generation Digital Network", an EDGE (Enhanced Data GSM Environment) network they've been overlaying for the past year and a half on top of their existing TDMA network to provide both voice and high-speed data service.

Paralleling AT&T on the other side of the border, what was originally the 900 pound gorilla of the Mexican cellular industry, Telcel also originally deployed TDMA equipment for digital service, and is now doing an EDGE upgrade/makeover of their cellular network. Telcel lags behind AT&T (who's somewhere around the 50% mark) with according to their official maps approximately 1/3rd of their service area providing GSM service (in addition to the existing TDMA), and in reality probably a fair amount less.

Now where things get really sticky is in what you consider to be "changed across the border" to be.

1. Many AT&T TDMA calling plans have provisions for voice service roaming in Mexico, using Telcel's TDMA network. You'll need to call customer service to have international roaming activated, at which time, calls made to your US phone number will be received on your phone in Mexico (for a roaming charge, of course).

2. AT&T does not have a voice roaming agreement for their GSM phones in Mexico (Telcel is the only service provider in Mexico who's converting to GSM, all of the noteworthy competitors are sticking with CDMA and its advanced variants). Telcel does currently offer GSM roaming to some Deutsche Telekom (T-Mobile) and Cingular customers.

3. You can either have a second Telcel phone number added to your existing AT&T TDMA phone if your phone has multiple NAM capabilities (many TDMA handsets do), or have AT&T service deleted from the phone and Telcel TDMA service programmed in.

4. In theory service for GSM phones should be switchable to a new carrier by simply removing and replacing the SIM "chip" in the phone with a SIM from the local provider. Unfortunately, in the case of AT&T "Next Generation" (GSM) customers, AT&T has had the nasty habit of SIM-locking their equipment so that the phones refuse to function with another provider's SIM installed. Depending on the popularity of the phone you may or may not find the equipment and code needed to remove the SIM-lock from the phone. You can also purchase your GSM equipment unlocked from another source, and then install an AT&T SIM into it for use in the US, but you miss out on AT&T's equipment subsidies by doing so.

In Reply To

I want to buy one of the new phones that allows for faster internet connections when they come out. Should I expect to have to wait quite awhile for that technology to reach across the border or will it be available when it's available in the US?

"High speed" data (>>56 Kb/sec) service is already available in a number of US markets in which 3G CDMA and/or EDGE equipment has been deployed. Such service is also available in some of the major metropolitan Mexican markets, although it seems that to date most of it has been targetted to corporate customers in Mexico. The big question will be whether you will actually want to avail yourself to the service in either the US or Mexico - it can be quite expensive. AT&T, which admittedly is on the high end of the spectrum is currently charging $20/month, with an additional $0.006 charged for every KB over the 8 MB allowance, on their ultra-high volume plan.

alleygata

Feb 1, 2003, 11:07 PM

Post #3 of 12 (2447 views)

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Re: [ET] Another Question About Cell Phones

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I knew we'd have a expert within our group. Thanks ET, you availed me of the information I needed.

morenasa

Feb 2, 2003, 1:37 PM

Post #4 of 12 (2411 views)

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Re: [ET] Another Question About Cell Phones

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That is certainly a wealth of information.....can you translate something for an average dimwit? The GSM thingy, does that mean that you have service in Mex and US without roaming charges? That would be too good to be true but thought I'd ask. I also have an AT&T phone that works perfectly well in Mexico but I'd like to get away from the roaming charges or lessen them if I can. For several reasons, I need to keep a cell phone with a US number.

Mereja

Feb 2, 2003, 1:48 PM

Post #5 of 12 (2409 views)

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Re: [morenasa] Another Question About Cell Phones

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I also have AT&T cell phone service. When I went to Mexico it worked almost everywhere that we went. For some reason I didn't get incomeing calls, although people could leave me a message and I could retrieve it. But I could call the US and within Mexico. I also had had to pay the roaming charges.

morenasa

Feb 2, 2003, 2:43 PM

Post #6 of 12 (2405 views)

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Re: [Mereja] Another Question About Cell Phones

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That's weird that you didn't get incoming, I got them all the time and when I answered, people thougt I was lying when i told them i was in Mexico. The reception was pretty clear.

Feb 2, 2003, 4:02 PM

Post #7 of 12 (2395 views)

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Re: [Mereja] Another Question About Cell Phones

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Mereja writes:
I also have AT&T cell phone service. When I went to Mexico it worked almost everywhere that we went. For some reason I didn't get incomeing calls, although people could leave me a message and I could retrieve it.

My first suggestion would be to contact AT&T Wireless International Services, rather than AT&T's standard customer care, and verify (a) that you've actually got international roaming activated, and (b) that you account is properly configured for such roaming. In certain fone phreak circles you'll also see comments made about early releases of phones having such problems, which are subsequently corrected by firmware updates, but locating and installing revised firmware can be an adventure in itself. I think a better lesson would be never to purchase a phone during the initial stages of its release (usually identifiable by your having to pay a premium for the phone).

Like another poster in the thread, during a recent trip to (a) Guadalajara and (b) various locations in Nayarit, I switched my phone (an AT&T dual mode TDMA/GSM unit) back on when I deplaned at GDL, and after a slightly longer pause than normal, the phone acquired Telcel's TDMA network, and hung onto it for the duration of the trip. Calls made to my US number were relayed flawlessly and the only weirdness was that I had to remember that calls made to the US were dialed in international format, and calls in Mexico always needed their area codes.

(This post was edited by ET on Feb 2, 2003, 5:54 PM)

Feb 2, 2003, 4:06 PM

Post #8 of 12 (2394 views)

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Re: [morenasa] Another Question About Cell Phones

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morenasa writes:
....can you translate something for an average dimwit? The GSM thingy, does that mean that you have service in Mex and US without roaming charges?

In this context, no.

weburke

Feb 27, 2003, 6:05 PM

Post #9 of 12 (2315 views)

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Re: [alleygata] Another Question About Cell Phones

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Even though T-Mobile and Telcel have an agreement for GSM service, I cannot receive or send calls in northern Baja. My cell phone number is a San Diego area code. I signed up for WorldClass service with T-Mobile and still can't use the phone (Samsung r225 GSM 900/1900) in Baja. Any suggestions as to my next move? Thanks.

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Mar 2, 2003, 1:03 PM

Post #10 of 12 (2291 views)

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Re: [weburke] Another Question About Cell Phones

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"weburke" writes:
Even though T-Mobile and Telcel have an agreement for GSM service, I cannot receive or send calls in northern Baja.

Considering that (a) Baja California (Norte) covers some 27,648 square miles and (b) you didn't describe what your phone is doing, it's really rather difficult to make any suggestions as to your next move, except perhaps to suggest that you withhold your favors from Ms. Zeta-Jones. Unfortunately for you however, is that last night while lounging on the bearskin rug in front of the fireplace with a tank of sulfur hexafluoride and an infrared spectrometer within ready reach (hey, this is the "Technical Mexico" forum, after all) Ms. Zeta-Jones pledged eternal fidelity to me, which means that any withholding probably won't have a significant impact.

1. I'm assuming you've got a "No Service" message on the phone's display.
(a) If incorrect, what does the phone display as the network name?
(b) If correct, what does the signal strength indicator show?
(b) If correct, when you set Network Select to "Manual" and use the scroll up and down keys, what are your choices?

2. Where in "northern Baja" are you attempting to use the phone?

3. Have you encountered other cellular users who are successfully making calls?
(a) With Telcel?
(b) With another carrier?

Mar 2, 2003, 1:06 PM

Post #11 of 12 (2288 views)

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Update re AT&T Roaming in Mexico

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In a previous post in this message thread I commented that AT&T only offered TDMA roaming in Mexico, while Deutsche Telekom/T-Mobile and Cingular offered GSM roaming on Telcel's budding but currently limited GSM network. As of 02/27/03 AT&T went live with roaming on this same GSM network, which naturally for AT&T Wireless customers can only be accessed using "Next Generation" (GSM) handsets and AT&T SIMs. AT&T continues to offer roaming for their TDMA customers and equipment using Telcel's TDMA network.

(This post was edited by ET on Mar 2, 2003, 1:11 PM)

Mar 2, 2003, 9:49 PM

Post #12 of 12 (2281 views)

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Re: [weburke] Additional Info Regarding T-Mobile Roaming Problem

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Synopsis of Private Message:
1. With phone set to "Automatic" network selection phone does not display network provider name. Message sequence of "No Service" followed by "Emergency Service Only" displayed. Weak to moderate signal strength.
2. Use Location - Tijuana - Ensenada Corridor
3. Other users with AT&T, Nextel, Sprint, and Verizon are using roaming service.

"weburke" - Immediately to the right of "Private\n Reply" you should see "Reply" which will post your message to the forum.

Well, in a quasi-tragic turn of events, Ms. Zeta-Jones dumped me for some guy with a dedicated purpose electron-capture detector equipped gas chromatograph ("please try to understand - it sees two orders of magnitude below your spectrometer and has 1/10th the latency time....it's what I need when I'm passing gas at Manny the Mannequin...."). Only a quasi-tragedy though, as I was only really keeping her around because she knew how to program the VCR and stop it from blinking "12:00" continuously. That and I was getting sick of her getting together with her hoodlum friends, drinking all the beer in the fridge, and staying up all night trying to hack my Xserve and gain root access.

My loss is your gain, however, as I no longer have any compunction about spilling the dirt on T-Mobile. It sounds like you've got at least 1 solvable problem, plus quite possibly another which isn't, at least immediately. I haven't worked with your model of phone, but the "No Service" -> "Emergency Service Only" sequence hints that your T-Mobile account hasn't been properly provisioned to allow for international roaming. The "Emergency Service Only" message is used by a number of cellular terminal/SIM combinations when a network you're not authorized to use is the only one detected (theoretically E911 is still supposed to be accessible, henceforth the "Emergency Service Only" label). As I indicated in my original reply to you, you should switch the phone to Manual Network Selection and note the names of the network(s) detected (You'll need to wait as the phone performs a scan to locate networks. Also make sure to scroll up or down to see if there's more than one network listed). Even an <<UNKNOWN>> entry on the list is of interest here, as it indicates that the phone is detecting the presence of a network ("unknown" simply indicates that there's no entry in the phone's lookup table for the MCC/MNC combination detected). While in the Manual selection mode you can also try to manually select (imagine that....) any network detected to see if this forces the phone into roaming.

As an alternative to the "Emergency Service Only" scenario painted above, you should also be aware, that in at least one mobile phone forum, your particular brand and model of phone has also been painted as resorting to the "Emergency Service Only" tag excessively because it's got a relatively small vocabulary. If this is the case about all you can do is take solace in the fact that you really didn't want a cellphone that's more literate than you are.

Even if it turns out to be an account provisioning problem, and you get international roaming activated, you shouldn't have huge expectations at present regarding GSM cellular service. As I indicated in my first posting in this message thread, Telcel is in the very early stages of GSM deployment. Although both Tijuana and Ensenada are listed by Telcel as having GSM service, (a) like a certain US provider who's initials are AT&T, Telcel seems to be rather optimistic in their listings of areas with GSM service, and (b) my guess is that Telcel is focusing the initial stages of their deployment on the commercial cores of urban areas. In such areas you'd be more likely to find early adopters of new technologies as well as those who have the greatest interest and need for roaming services (which are worth big dollars). Additionally, in the particular case of the 3G GSM overlay, urban cores are where you'd expect to find the highest demand for the profit-generating GPRS data network, which is one of the motivators for the 3G upgrade in the first place. As it's not a major commute corridor, I wouldn't expect the actual highway connecting Tijuana to Ensenada to get GSM service until after deployments are completed in the associated cities (as well as other cities in Mexico) and/or if/when Telcel activates GSM-800 service (which won't do you any good with your existing phone).

Finally, neither Nextel, Sprint, or Verizon are using Telcel as their Mexican roaming partners, as they're using incompatible technologies (iDEN in the case of Nextel, CDMA for Sprint and Verizon). Until three days ago, AT&T was only roaming on Telcel's TDMA network, which is considerably more extensive, at present, than Telcel's GSM network. If you're dead set on getting roaming service in the Tijuana/Ensenada corridor right now, you should consult with some of these users to get their impression on the quality of their service.

Now pay David $30 USD for membership, or I'll make sure Ms. Zeta-Jones denies you service forever.....