Friday, August 31, 2007
AMPS analog cellphone service
In this post, I mentioned the old analog cell service and its suitability for rural use where towers are few and far between. This service is a matter of contention among users who keep abreast of such things, because on one hand it uses more bandwidth and consumes more power per active link (conversation), lacks some of the features of newer systems such as text messaging, multimedia and automatic GPS location; while on the other hand, compared to newer digital formats it has much greater range, is a truly standardized format with more support in the hinterlands, has much better audio quality in the presence of a strong signal, and is more likely to simply get more noisy with poor signal strength rather than dropping the call altogether. Also, there are the 3-watt bag- and hard-mount AMPS phones with external antennas for the really sparsely-populated areas.
As with so many other things it comes down to city versus rural, where the city dwellers are unaware and/or apathetic if not downright hostile towards the concerns of rural dwellers, and those who live or spend a lot of time in the rural areas lose out simply because we represent a tiny minority compared with the masses in the cities. City-based digital-network users tend to believe, erroneously, that the presence and use of AMPS analog service somehow reduces or interferes with their service. In fact that's not the case, because most cell towers in highly-populated areas don't really need to support AMPS at all, and even if they do the system can be and is configured to drop the AMPS calls in favor of the digital, in the event that the system becomes overloaded. So a system can easily be configured to accept AMPS calls during low-usage times, and reject them during times of high usage.
It's a moot point anyway, because practically everybody has a digital phone. Digital phones are so cheap that the service providers literally give them away to facilitate selling the service. The only people who have AMPS phones are those who seek out and buy one specifically to use in rural areas where the digital service is sparse or nonexistent, and even those people certainly also have a digital phone to use when the service is available, because that service is cheaper and offers more features. The majority of AMPS service is either prepaid or paid per-call via calling card or credit card, and both are more expensive than digital service.
Currently, the existing AMPS service is required by law to be maintained. This law is due to expire February 2008, but the FCC has already pushed the expiration date back a couple of times, and may continue to do so. Even if the law does expire, it is doubtful that the system will be dismantled in rural areas as long as it continues to be used. So if you spend much time beyond reach of the digital networks, buy yourself an analog phone on Ebay, get some prepaid service and use it, so we don't lose it!
In researching this material, I found some really interesting comments on one of the newsgroups. I have reproduced those comments here:
"Through all the searching I found one thing that kept
hitting me in the face every time I brought up a new page.
It generally followed a few lines of thinking.
AMPS will be replaced by dedicated CDMA systems.
AMPS will no longer be installed on newer installations.
FCC has removed the requirement for AMPS in new areas.
AMPS systems will be removed when the towers are needed for newer systems.
AMPS space will no longer be supported on new CDMA systems.
You need dual mode/band phones to set up service.
You can't setup a AMPS phone.
You can't buy an AMPS phone.
They don't sell CDMA car phones.
The US will take Australia's example.
Australia's major cell phone company is switching over
To digital, AMPS will no longer be supported.
The magical date I usually see is around five years
for the magical end of the AMPS world.
MY disbelief was running high.
Do they think that no one exists outside of the large cities?
So I had to make a public rant.
It helps to let off some steam.
It is hard to comprehend why AMPS service would ever become unavailable.
As long as the 800meg cell band is used, AMPS should be supported on every
It would hardly cost them anything to make have multimode rack mount
FM is a base mode that can be engineered into any 800meg rack mount cell
What really puzzles me is why they have to have a dedicated mode for a
As a person who works with a lot of radio related communications equipment,
it boggles my mind why a network would be limited to one digital mode.
Every 800meg cell transceiver slot should be occupied with a standard unit.
It can work in AMPS, TDMA, CDMA, 800meg GSM and any other digital mode
That a multi mode DSP receiver and transmitter can be made to run.
When a new digital mode comes out for the 800meg band, you just
update the firm ware to handle it.
Every slot will be able to handle any form of communication on demand.
A cell phone that is roaming from another area with a different native
will be able to operate in its native mode irrelevant of the system's native
The cell phone companies need to learn a lesson from the computer industry.
There is no need to adopt a standard digital mode.
(a computer can interface with all forms of communications channels)
There is no need to obsolete old equipment.
(An old computer will interface with the web just the same as a new one
Everything is upgradeable.
(via software, you can increase the computers capabilities without
changing any hardware.)
Everything is backward compatible.
If you don't have a V90 modem and you dial in to
the service provider, it will default to a legacy mode
without any interruption.
Your computer is still talking to the same node modem but the
node modem can operate in almost any mode.
You can dial in with an old 300bps modem and it will
connect without a hitch.
It works, I have tried :)
An old computer can interface the new network.
It won't be able to use any of the newer features but
It will be able to operate up to it's original design.
That is the design basses that should be used for the cellular network.
They shouldn't care what types of modes your phone will use.
The network can use all of them.
Now that I think about it, that would allow for some interesting
dynamic traffic control if all user phones and all cell transceivers
could operate in any mode.
During low usage hours, everyone will have full voice channels.
When usage grows, it will start doubling up people.
The doubling up will depend on the modes the user phones are capable of.
If channel usage reaches maximum levels then users with high band width
usage could be bumped off to accommodate more narrow band phones.
The people with new phones will be unaffected but the people that
Are just in the city for the day may get bumped off once in a while.
They won't mind though, because they are in the city very rarely.
The places they are normally around will have no problem with the older
Newer phones could access newer features but older phones will be limited
to what they came out with.
The people in the boondocks won't care because they don't use the features
All older phones will be usable in newer systems.
All newer phones will be usable in older systems.
But the cell phone production companies couldn't make
a killing from designed obsolescence."
"Remote areas, where AMPS is the only service, will almost
certainly not have AMPS shut down, at least by the rural CDMA/AMPS
carriers. There are several reasons for this. First, a lot of emergency
call boxes are in areas with no digital coverage, and these call boxes
use AMPS. Second, a lot of the AMPS coverage is by smaller carriers in
rural areas, and AMPS represents roaming revenue. Third, AMPS provides
the only coverage for locals in a lot of the area covered by these
carriers. There is no cost savings in turning off AMPS unless there is a
capacity issue, and the rural carriers don't have capacity issues.
For AMPS areas that are currently covered only by Cingular, they will
almost certainly turn off AMPS even in their areas that have no digital
coverage. For example, I was recently out in the Florida Everglades,
roaming onto Cingular's AMPS network from my Verizon tri-band phone. 95%
of Cingular's customers can't use that AMPS network, and had no
coverage. It makes Cingular look bad when only Verizon, Sprint, Alltel,
etc's customers can use one of their networks. Hence, I think that
Cingular will turn of all AMPS as soon as they can, even though this
means vast areas with no coverage will be created. Fortunately, there
are not a lot of areas where Cingular is the only AMPS carrier.
Metro areas with rural areas surrounding them, will suffer when AMPS is
permitted to be turned off. For example, in the San Francisco Bay Area,
there are a lot of areas outside the urban core, sometimes only a few
miles from the urban core, where AMPS is the only coverage you're able
to get. A lot of these areas are city, county, state, and national
parks, where they are unlikely to permit enough towers to cover the
areas in digital, but where you currently get decent AMPS coverage from
towers outside the parks. All the coverage in these areas will be lost
when AMPS is turned off. This is good news for Cingular, which has much
poorer coverage, at least in my area, by virtue of their lack of AMPS.
I'm hoping that the state of California will insist that all the
roadside call boxes remain operational, which will give AMPS a bit more
life, even in the semi-urban areas.
Even without AMPS, Verizon's network is better than Cingular's, so
PagePlus is still a good choice. "