How GAIT really works...

On 10 Nov 2003 21:38:07 -0800, [email protected] (John Klug) wrote:

>Standard GSM has a 35 km limit. You get a signal that is useless from
>what I understand past the limit. You can send SMS, but no voice
>transmission is possible. Therefore, if the gate phone were to pick up
>a standard GSM tower past the 35km limit, and the phone won't let you
>switch to TDMA, you would not be able to make a call. There is
>something called extended range GSM, but will any US carriers use it?
>See http://www.ericsson.co.nz/press/2000...vodafone.shtml

There is no "gate" phone! There is however GAIT.

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› See More: How GAIT really works...

I'm Sure you can squeeze in an SMS in the outskirts of the cell. its only a
few bytes of data
"John Henderson" <[email protected]> wrote in message
news:[email protected]...
> And the 35 km distance limit for normal GSM cells applies equally
> to SMS.
>
> John
>

Dimitris Kiamilis wrote:

> I'm Sure you can squeeze in an SMS in the outskirts of the cell. its only a
> few bytes of data

Not if you don't have a valid value for Timing Advance (TA) you
can't.

TA is a 6-bit integer field (valid values from zero to 63), with
each increment corresponding to an extra 553.5 metres from the BTS.

John

> > I'm Sure you can squeeze in an SMS in the outskirts of the cell. its only a
> > few bytes of data
>
> Not if you don't have a valid value for Timing Advance (TA) you
> can't.
>
> TA is a 6-bit integer field (valid values from zero to 63), with
> each increment corresponding to an extra 553.5 metres from the BTS.
>
> John
So the presence of a GSM signal will cause you not to be able to use a
GAIT phone when outside the 35km limit. Since I frequently make calls
using TDMA in this situation due to terrain, there is no point to ever
getting a GAIT phone, unless they allow you to manually select TDMA
like Verizon does with AMPS. A GAIT phone would be useful if GSM were
only available on the PCS band, and TDMA at the cellular band.

I think it is interesting that the SE T62U and Siemens S46 are both
gone from ATTWS web site. So maybe GAIT really doesn't work very well
for ATTWS.

"John Klug" <[email protected]> wrote:
> > > I'm Sure you can squeeze in an SMS in the outskirts of the cell. its
only a
> > > few bytes of data
> >
> > Not if you don't have a valid value for Timing Advance (TA) you
> > can't.
> >
> > TA is a 6-bit integer field (valid values from zero to 63), with
> > each increment corresponding to an extra 553.5 metres from the BTS.
> >
> So the presence of a GSM signal will cause you not to be able to use a
> GAIT phone when outside the 35km limit. Since I frequently make calls
> using TDMA in this situation due to terrain, there is no point to ever
> getting a GAIT phone, unless they allow you to manually select TDMA
> like Verizon does with AMPS. A GAIT phone would be useful if GSM were
> only available on the PCS band, and TDMA at the cellular band.
>
> I think it is interesting that the SE T62U and Siemens S46 are both
> gone from ATTWS web site. So maybe GAIT really doesn't work very well
> for ATTWS.

As I understand it, ATTWS didn't want to keep selling phones that would
require a commitment to multiple systems any longer than they'd have to.
The REALLY would rather force everyone to GSM.

As for the manual select, the S46 allows TDMA only, GSM only or Automatic.
In some places, there are both signals and you can take your pick.

John Klug wrote:
>>>I'm Sure you can squeeze in an SMS in the outskirts of the cell. its only a
>>>few bytes of data
>>
>>Not if you don't have a valid value for Timing Advance (TA) you
>>can't.
>>
>>TA is a 6-bit integer field (valid values from zero to 63), with
>>each increment corresponding to an extra 553.5 metres from the BTS.
>>
>>John
>
> So the presence of a GSM signal will cause you not to be able to use a
> GAIT phone when outside the 35km limit. Since I frequently make calls
> using TDMA in this situation due to terrain, there is no point to ever
> getting a GAIT phone, unless they allow you to manually select TDMA
> like Verizon does with AMPS. A GAIT phone would be useful if GSM were
> only available on the PCS band, and TDMA at the cellular band.
>
> I think it is interesting that the SE T62U and Siemens S46 are both
> gone from ATTWS web site. So maybe GAIT really doesn't work very well
> for ATTWS.

I have an SE T62u, and I have manually selected "TDMA Only".

Menu -> Settings -> Networks -> Protocol Stack

Options include:
- GSM Pref
- TDMA Pref
- GSM Only
- TDMA Only
- TDMA Persistent
- GSM Home Pref
- Use SIM

I would also like to add that in my home area, when I lose Cingular
signal, I often roam on AT&T. The only time I notice this is when I get
a message from AT&T Wireless Services when I try dialing *89 to check my
e-mail.

AD

In article <[email protected]>,
[email protected] says...
> So the presence of a GSM signal will cause you not to be able to use a
> GAIT phone when outside the 35km limit. Since I frequently make calls
> using TDMA in this situation due to terrain, there is no point to ever
> getting a GAIT phone, unless they allow you to manually select TDMA
> like Verizon does with AMPS. A GAIT phone would be useful if GSM were
> only available on the PCS band, and TDMA at the cellular band.

I'm a bit confused. I think you're over analyzing. From what I've seen
so far in north Texas, Cingular GSM and TDMA are almost EXACTLY the same
footprint. GSM may even be a bit clearer at the fringes--where I loose
the DFW signal to the south of the city TDMA would get "choppy" the last
few miles but GSM holds a solid call until Dobson TDMA takes over. Even
if a GAIT phone lost the GSM signal in a Cingular area Cingular TDMA
would take over but that's going to be VERY rare--so far I've only
noticed it once in DFW. To be a problem in the home area it would have
to be a very weak GSM signal--just enough to cause the phone to try to
retain it instead of switching to TDMA. I have not seen such an area.
Cingular apparently has done an excellent job overlaying.

The only other time it would be a problem is if 1) home or preferred
carrier doesn't have BOTH GSM and TDMA, 2) you hit an area that looses
GSM but has TDMA from another carrier, and 3) the other carrier is
banned so you cannot roam on them. That's not likely to happen if
you're actually roaming outside your home area--even if you loose the
GSM carrier odds are the phone will be perfectly happy with the TDMA
carrier. You might miss some inbound calls if you're switching back and
forth rapidly while the system tries to keep up with you. Example--
Brownwood TX has weak T-Mobile GSM but strong Dobson TDMA. My 6340i
would lock onto T-Mobile in hilly areas but would attempt to switch to
TDMA in low areas but usually by the time it registered I'd be back in
T-Mobile. Interesting tidbit--since Cingular went GSM in my home area
the phone no longer selects T-Mobile GSM at all in Brownwood--stays on
Dobson TDMA. Since both are preferred I would have thought a GSM
carrier would have higher priority but apparently not always.

So really the only time this would bite someone is if they're trying to
use a GAIT phone in a Cingular GSM-only area where the TDMA carrier is
banned. In which case the GAIT phone is probably not officially
supported anyway. California anyone? But even then the GAIT phone
wouldn't be any WORSE than a GSM-only phone.

--
Jud
Dallas TX USA

On Tue, 18 Nov 2003 15:35:25 GMT, Jud Hardcastle
<[email protected]> wrote:

> In article <[email protected]>,
> [email protected] says...
>> So the presence of a GSM signal will cause you not to be able to use a
>> GAIT phone when outside the 35km limit. Since I frequently make calls

Why are you people cluttering up a.c.alltel and a.c.cdma with GSM crap?

Never mind, you use ATT TDMA/GSM, so we already know - you're clueless.

--
Mark

Jud Hardcastle <[email protected]> wrote in message news:<[email protected]>...
> In article <[email protected]>,
> [email protected] says...
> > So the presence of a GSM signal will cause you not to be able to use a
> > GAIT phone when outside the 35km limit. Since I frequently make calls
> > using TDMA in this situation due to terrain, there is no point to ever
> > getting a GAIT phone, unless they allow you to manually select TDMA
> > like Verizon does with AMPS. A GAIT phone would be useful if GSM were
> > only available on the PCS band, and TDMA at the cellular band.
>
> I'm a bit confused. I think you're over analyzing. From what I've seen
> so far in north Texas, Cingular GSM and TDMA are almost EXACTLY the same
> footprint. GSM may even be a bit clearer at the fringes--where I loose
> the DFW signal to the south of the city TDMA would get "choppy" the last
> few miles but GSM holds a solid call until Dobson TDMA takes over. Even
> if a GAIT phone lost the GSM signal in a Cingular area Cingular TDMA
> would take over but that's going to be VERY rare--so far I've only
> noticed it once in DFW. To be a problem in the home area it would have
> to be a very weak GSM signal--just enough to cause the phone to try to
> retain it instead of switching to TDMA. I have not seen such an area.
> Cingular apparently has done an excellent job overlaying.
>
> The only other time it would be a problem is if 1) home or preferred
> carrier doesn't have BOTH GSM and TDMA, 2) you hit an area that looses
> GSM but has TDMA from another carrier, and 3) the other carrier is
> banned so you cannot roam on them. That's not likely to happen if
> you're actually roaming outside your home area--even if you loose the
> GSM carrier odds are the phone will be perfectly happy with the TDMA
> carrier. You might miss some inbound calls if you're switching back and
> forth rapidly while the system tries to keep up with you. Example--
> Brownwood TX has weak T-Mobile GSM but strong Dobson TDMA. My 6340i
> would lock onto T-Mobile in hilly areas but would attempt to switch to
> TDMA in low areas but usually by the time it registered I'd be back in
> T-Mobile. Interesting tidbit--since Cingular went GSM in my home area
> the phone no longer selects T-Mobile GSM at all in Brownwood--stays on
> Dobson TDMA. Since both are preferred I would have thought a GSM
> carrier would have higher priority but apparently not always.
>
> So really the only time this would bite someone is if they're trying to
> use a GAIT phone in a Cingular GSM-only area where the TDMA carrier is
> banned. In which case the GAIT phone is probably not officially
> supported anyway. California anyone? But even then the GAIT phone
> wouldn't be any WORSE than a GSM-only phone.
If you are correct, and the phone can switch to TDMA, and the carrier
will let you used TDMA, even though that same carrier has GSM, you
would be right. I think you are talking about different signals from
different carriers, and if you can use GSM at all, you are not past
the 35km limit.

I guess I was thinking of AMPS not being usable on TDMA phones except
when there was no TDMA signal at all.

The reason why I am past the 35km limit is that the closest tower is
at an elevation of 860 feet, and we are at an elevation of 1300 feet,
and the tower is only 300 feet tall, so it is well below the horizon,
and I have verified that it cannot be reached via a YAGI antenna, and
I am in a place with almost no population and a coverage hole, so I go
for the next closest tower which is at the same elevation as me, and a
height of 400 feet. Basically I am luck to get phone service at all.