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You all remember the old AMPS networks

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Thought I'd ask here because y'all seem pretty knowledgeable about telecom. Most mobile network operators enthusiastically killed analog cellular in Feb 2008, but there were reports of really really small operators keeping analog on reportedly up until around 2010 or 2011. None of you all would happen to know about these smaller operators would you?

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Got a fork stuck in them by the Evil Empire: AT&T, T-Mobile, Verizon., and Sprint.

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Got a fork stuck in them by the Evil Empire: AT&T, T-Mobile, Verizon., and Sprint.

Acquisitions?

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Shutdowns.

In fact, for the most part, but apparently not entirely. Around the Vancouver, WA area there appears to be a small(?) possibly forgotten-about AMPS carrier still operating. Early last year A friend of mine got his dad's old Motorola brick phone working again and for shits and giggles tried to make a call, and managed to get a CBCD error message back (sounded like the old Cellular One announcer guy but had no message number or comoany identifier). In FM. In 2015. And no, I'm certain it wasn't some smartass kid with a freebanded Chinese ham radio or something like that. So either there must be a small-time AMPS company still providing legacy service (Vancouver is quite a large urban area) or he must have woken up some long-forgotten but still apparently functional equipment somewhere.

Yet I can scan 800 MHz on my PRO-2004 and I don't hear anything. There is an entire cellular band (lower IIRC) that is for the most part silent, so I'm guessing that's where it lives. Strange thing is there is no control channel or anything like that (that I've been able to receive) so it's probably some weird setup that listens for a mobile signal and only does its thing as needed, on demand. The other band has the usual bumper-crop of C/DTMA/GSM hash.

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Shutdowns.

In fact, for the most part, but apparently not entirely. Around the Vancouver, WA area there appears to be a small(?) possibly forgotten-about AMPS carrier still operating. Early last year A friend of mine got his dad's old Motorola brick phone working again and for shits and giggles tried to make a call, and managed to get a CBCD error message back (sounded like the old Cellular One announcer guy but had no message number or comoany identifier). In FM. In 2015. And no, I'm certain it wasn't some smartass with a freebanded ham radio or something like that. So either there must be a small-time AMPS company still providing legacy service (Vancouver is quite a large urban area) or he must have woken up some long-forgotten but still apparently functional equipment somewhere.

Yet I can scan 800 MHz on my PRO-2004 and I don't hear anything. There is an entire cellular band (lower IIRC) that is for the most part silent, so I'm guessing that's where it lives. Strange thing is there is no control channel or anything like that (that I've been able to receive) so it's probably some weird setup that listens for a mobile signal and only does its thing as needed, on demand. The other band has the usual bumper-crop of C/DTMA/GSM hash.

No control channel? That's pretty damn odd. Did you try using an SDR card too?

As far as my understanding goes all old mobile stations have a tendency to just latch onto whatever it finds operating. Did any part of the phone's programming need to be tweaked or was it just him kinda powering on the unit and having a realization of "holy shit, it's found a system to associate with"?

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It was him just kinda powering on the unit and having a realization of "holy shit, it's found a system to associate with". Which is why we figured that either it's an extremely limited-service "on demand" legacy thingy that only activates when it detects a mobile (saves electricity, I guess), or maybe some little private system used internally by some local company or other. The latter may explain the lack of any message identification.

When he first turned the device on, there were no signal bars after the "S" on the display (the "NoSvc" indicator lamp was even lit.) He then hit SND and the system came to life. The phone reported full signal level for about two minutes afterward, at which point the signal dropped completely (base unit probably turned off automatically). That was when we figured "hmm, maybe this is something nobody's supposed to know about" and let it stand at that.

Neither of us can figure out with any certainty where it's based either. Best guess I can come up with is it must be in Portland somewhere, as his house at the time was in southeastern Vancouver and had a good enough line of sight and Portland seems to have lots of weird/esoteric/mysterious stuff like that on the VHF/UHF bands. We even later tried it from my place about 8 miles north and couldn't get it to do anything. So it must be in north Portland or Camas someplace.

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It was him just kinda powering on the unit and having a realization of "holy shit, it's found a system to associate with". Which is why we figured that either it's an extremely limited-service "on demand" legacy thingy that only activates when it detects a mobile (saves electricity, I guess), or maybe some little private system used internally by some local company or other. The latter may explain the lack of any message identification.

When he first turned the device on, there were no signal bars after the "S" on the display (the "NoSvc" indicator lamp was even lit.) He then hit SND and the system came to life. The phone reported full signal level for about two minutes afterward, at which point the signal dropped completely (base unit probably turned off automatically). That was when we figured "hmm, maybe this is something nobody's supposed to know about" and let it stand at that.

Neither of us can figure out with any certainty where it's based either. Best guess I can come up with is it must be in Portland somewhere, as his house at the time was in southeastern Vancouver and had a good enough line of sight and Portland seems to have lots of weird/esoteric/mysterious stuff like that on the VHF/UHF bands. We even later tried it from my place about 8 miles north and couldn't get it to do anything. So it must be in north Portland or Camas someplace.

If you're willing to delve into it further, grab a tri-band phone with a field test mode and enter it when the phone associates with this clearly emaciated network, you should be able to view the SID of the network somewhere with that mode. Use that and compare it against the current list of networks

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Interesting! The next time you have an AMPS phone handy, would you mind making a recording of the message you get? I've heard in a lot of COs, the AMPS gear never got removed after being shut down. In one case - I think in Sydney, it even helped support the roof of the building. Maybe some bored engineer (or someone who found an unlocked door) decided it'd work much better when it's plugged in.

 

Anyway, I dunno if it ever got shut down, but I've heard some Alaskan operator ran AMPS past the 2008 shutdown date.

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Interesting! The next time you have an AMPS phone handy, would you mind making a recording of the message you get? I've heard in a lot of COs, the AMPS gear never got removed after being shut down. In one case - I think in Sydney, it even helped support the roof of the building. Maybe some bored engineer (or someone who found an unlocked door) decided it'd work much better when it's plugged in.

 

Anyway, I dunno if it ever got shut down, but I've heard some Alaskan operator ran AMPS past the 2008 shutdown date.

Not sure if many are aware but that February 2008 date was just the FCC saying "you don't have to continue to operate AMPS," not a "you HAVE to shut off AMPS"

I would LOVE to see an AMPS phone associated with an analog system this year. Maybe I'll use my tax money to travel to a place where it works

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I've heard Cuba still runs AMPS from an AXE-MSC. You might be able to rent a boat near Key West with some really directional AMPS antennas or something. Speaking of MSCs, I started looking around the Portland area to see where the signal scratchytcarrier talked about could be coming from, and it looks like Sprint can't afford to keep their Tigard MSCs (or Tie Guard if you're using the KXPD pronounciation :lol: ) on anymore, so now it's just a POI to some other switch. By the way he described the voice, I'm betting it's T-Mobile providing the signal.

 

707-971-0509 is a recording from one of their California switches (DMS, I think? Tough call without a ring to listen to). 201-205-6089 is a Sprint 5ESS.

 

EDIT: According to npanxxsource, a prefix for the Tigard MSC was updated - presumably to the POI in March 2015. If that was theirs, you might've caught it during the last few months it was running.

Edited by ThoughtPhreaker
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I've heard Cuba still runs AMPS from an AXE-MSC. You might be able to rent a boat near Key West with some really directional AMPS antennas or something. Speaking of MSCs, I started looking around the Portland area to see where the signal scratchytcarrier talked about could be coming from, and it looks like Sprint can't afford to keep their Tigard MSCs (or Tie Guard if you're using the KXPD pronounciation :lol: ) on anymore, so now it's just a POI to some other switch. By the way he described the voice, I'm betting it's T-Mobile providing the signal.

 

707-971-0509 is a recording from one of their California switches (DMS, I think? Tough call without a ring to listen to). 201-205-6089 is a Sprint 5ESS.

 

EDIT: According to npanxxsource, a prefix for the Tigard MSC was updated - presumably to the POI in March 2015. If that was theirs, you might've caught it during the last few months it was running.

What is a POI?

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Point of Interconnect. I think the basic idea is like if you have a switch that serves a large number of ratecenters, you'll need a trunk group from it to the tandem switch serving it.

 

So let's say for example you've got a switch in Washington DC or wherever, but you want to plug in a bunch of channel banks and give dialtone to random people in the Blue Ridge mountains. You can totally run some cable down there and do it, but the problem is, your switch homes off the intra-LATA tandem in DC as it should. To accomadate the local calling area of everyone you're going to serve, you also need to get some trunks to the intra-LATA tandem in, say, Culpeper, and establish an exchange for them to be reached on/to reach the other local exchanges. When you're doing that, you're not allocating it to the switch, but to a point of interconnect between you and the Culpeper tandem, and the CLLI code will reflect that.

 

Because regulatory regimes are stupid, you can't legally (to my knowledge) give free local calls from your DC subscribers to the Culpeper area even though you have trunks to it from your switch; they have to use a long distance provider to dial that. Coin and operator calls are a little more of a grey area. I know from Portland, they have trunks from TOPS to the Salem tandem, and you'd hit that trunk group making ACTS calls. I dunno what those trunks were considered legally, but you could theoretically set up an automatic operator IVR to get around that restriction.

 

That's how I understand it anyway. Can someone who has more of a clue about this chime in?

Edited by ThoughtPhreaker
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Point of Interconnect. I think the basic idea is like if you have a switch that serves a large number of ratecenters, you'll need a trunk group from it to the tandem switch serving it.

 

So let's say for example you've got a switch in Washington DC or wherever, but you want to plug in a bunch of channel banks and give dialtone to random people in the Blue Ridge mountains. You can totally run some cable down there and do it, but the problem is, your switch homes off the intra-LATA tandem in DC as it should. To accomadate the local calling area of everyone you're going to serve, you also need to get some trunks to the intra-LATA tandem in, say, Culpeper, and establish an exchange for them to be reached on/to reach the other local exchanges. When you're doing that, you're not allocating it to the switch, but to a point of interconnect between you and the Culpeper tandem, and the CLLI code will reflect that.

 

Because regulatory regimes are stupid, you can't legally (to my knowledge) give free local calls from your DC subscribers to the Culpeper area even though you have trunks to it from your switch; they have to use a long distance provider to dial that. Coin and operator calls are a little more of a grey area. I know from Portland, they have trunks from TOPS to the Salem tandem, and you'd hit that trunk group making ACTS calls. I dunno what those trunks were considered legally, but you could theoretically set up an automatic operator IVR to get around that restriction.

 

That's how I understand it anyway. Can someone who has more of a clue about this chime in?

Ohh, interesting.

Might there exist a group of people that actively seek out these old systems? I sincerely believe someone out there cares enough to do so

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Er, I'm confused. The POI thing is a pretty common arrangement for most CLECs, and TOPS (or OSPS) tandems are in almost every local calling area. Are we talking about AMPS again?

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Er, I'm confused. The POI thing is a pretty common arrangement for most CLECs, and TOPS (or OSPS) tandems are in almost every local calling area. Are we talking about AMPS again?

Yep, AMPS

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If I remember the phone had a 206-901 number, which would be 360 today but has undoubtedly been reassigned probably several times. 901 is still in use today for cell phones here (old Cellular One exchange). (PTLDOR62CM3)

Interesting! The next time you have an AMPS phone handy, would you mind making a recording of the message you get? I've heard in a lot of COs, the AMPS gear never got removed after being shut down. In one case - I think in Sydney, it even helped support the roof of the building. Maybe some bored engineer (or someone who found an unlocked door) decided it'd work much better when it's plugged in.

I'll try to remember to ask him next time I see him, but I don't know if he still has it working. I'm pretty sure it can be recorded with an induction coil OK.

EDIT: According to npanxxsource, a prefix for the Tigard MSC was updated - presumably to the POI in March 2015. If that was theirs, you might've caught it during the last few months it was running.

I think we did it back in late January or maybe February, so if that's the case the thing might be extinct by now. I remember it was very cold that day and began snowing that evening on my way home.

EDIT: Boeing has a big factory/office in Gresham which is directly south of him, and Furuno, Sharp, Underwriters, Wafertech/TSMC and (I think) Raytheon all have facilities on the vancouver-facing side of Camas up on NW Pacific Rim Blv & SW 34th. So if it is a private system rather than a telco (an AMPS PBX?) it might be one of them (pobably Boeing or Wafertech since they're the biggest). There are also the VA hospital and OSHU in west Portland but I think they're too far away to hit.

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tumblr_o0jpwe9VQu1ut5dmlo1_1280.png

 

I got this bag phone last month and was playing around with it to see if there was some tiny chance that it could connect to any network. As I suspected, there aren't any crumbling remains of AMPS networks anywhere near me. An interesting feature about this phone is there's an "Aux Out" which apparently was for sending faxes. Can't imagine lugging all of that around and plugging everything into the 12v jack in your car...

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Now that I've been thinking about it, imagine how nice an AMPS implementation of OpenBTS would be

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Now that I've been thinking about it, imagine how nice an AMPS implementation of OpenBTS would be

Unfortunately OpenBTS is GSM only.

But there's at least one hobbyist made AMPS basestation.

 

http://www.idesignz.org/AMPS/AMPS_BS.html

 

Some old AMPS cellphone testsets available as surplus can likely also function as a limited basestation.

The GSM and NMT one's do that.

 

Now if I could just source one for the NMT450 network that used to be used around here...

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By the way he described the voice, I'm betting it's T-Mobile providing the signal.

T-Mobile? That doesn't make too much sense, T-Mobile (and its predecessors VoiceStream and Omnipoint) never operated analog networks. Matter of fact, neither did Sprint. T-Mo and Sprint were all digital from their inceptions.

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Really? I assumed it'd be one of the big four; Sprint and T-Mobile are the only two with male voices. Guess it shows how much I pay attention to cellular.

 

Anyway, definitely still interested in where this thing is coming from.

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By the way he described the voice, I'm betting it's T-Mobile providing the signal.

T-Mobile? That doesn't make too much sense, T-Mobile (and its predecessors VoiceStream and Omnipoint) never operated analog networks. Matter of fact, neither did Sprint. T-Mo and Sprint were all digital from their inceptions.

 

my first cell phone was an omnipoint "flip" phone... the flip was just a small plastic piece that covered the numbers when flipped closed... around 1996 or so.... 

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T-Mobile (and its predecessors VoiceStream and Omnipoint) never operated analog networks


Actually there were areas where Voicestream must have had arrangements to carry AMPS traffic, probably under contract on another (independent?) company's base stations. About 20 years ago or so when mom and I were on highway 101 heading south toward Cannon Beach, she wanted me to try and call dad on her Micro-TAC, which I am positive was an all-AMPS fone. (There was no GSM service here until around 2000ish. I think Portland might have had it before then.) The signal was slightly better than terrible between the Sunset highway ramps and Cannon Beach. I could still make out the error message that identified it as Voicestream, which it was apparently roaming on there. But I think Voicestream AMPS networks (gateways?) were probably few and far between. So either I was getting Seaside or (probably) some little hole-in-the-wall indy with a tower somewhere in the mountains and microwave or wire backhaul to Astoria or wherever. That was the only place I remember ever hearing it on AMPS. It must not have lasted long because the following summer we went there and I tried calling from around that same area, not only was the signal orders of magnitude better (still pretty awful) but it was roaming on Airtouch.

The Columbia River gorge was a mix of Cell One, Airtouch and I.I.R.C. GTE Mobilenet depending where you were. Making AMPS calls heading northbound on highway 35 coming down Mount Hood, in the mid to late 90s was always pretty, um... interesting. Between Government Camp and Hood River, it was handoff city for maybe a good 30 miles. Once you finally did hit the gorge of course, its topology made AMPS calling next to impossible since you not only had severe multipath and fading at times but also the capture effect to deal with. Then once you finally got east of Arlington and into the columbia basin you never really knew which carrier you'd be roaming on from one moment to the next, since radio signals propagate so well on that side of the cascades. Go capture effect!

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By the way he described the voice, I'm betting it's T-Mobile providing the signal.

T-Mobile? That doesn't make too much sense, T-Mobile (and its predecessors VoiceStream and Omnipoint) never operated analog networks. Matter of fact, neither did Sprint. T-Mo and Sprint were all digital from their inceptions.

 

 

I leave this for your consideration: https://en.wikipedia.org/wiki/Western_Wireless_Corporation

Edited by JCSwishMan33
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My (dumb) theory as to why cellular analog AMPS was shut down:

I am thinking it was to prevent analog-based voice encryption, which could have become prevalent. But it's a dumb theory with no evidence, since the encryption could happen in the headphone before it hits the phone.

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