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Wired Voice and Data to Cellular Options?
otterboy asks: "I am involved with a remote scuba diving operation in Northern British Columbia. The lodge has a regular wired handset, with a wire running up to the top of a nearby mountain. At the top of the mountain sits a little shack, which contains a cell phone, a big antenna, and a black box from Motorola. That box provides an RJ11 jack into which we can plug the 'regular' phone, which allows us to use the cell link from the regular wired phone in the lodge, since the only cell signal we can get is at the top of this mountain. We also use a GSM modem (over the 'regular' phone line, which gets converted to a cell signal up on the mountain), but the best rate we can get is about 4.8kbs. According to Motorola, this is a limitation of their converter. I've looked at Cellsocket, but it deals only with voice. Does anyone know of a converter with better data performance, or are we stuck with Motorola?"
No questions asked. You use their network, you use their hardware and suck up all the problems with it.
I know, it's not nice.
I've seen GSM modems, plug one into a dirt cheap laptop (ebay), then use 802.11 and a good antenna to get the signal down. Means you have two phone lines, but it is an option.
The other thing that comes to mind is starband is two-way satalite, which might fit your needs better.
There are other converters, or have been from time to time. I suspect all have a similear limit. Each time you do a digital-analog conversion you lose something, and if you think about it, you are adding anouther digital-analog step. GSM itself is 14.4k IIRC, so how much can you get, for CD sound you figgure double the sampeling rate to get acceptable sound, you 8k is more than half the sampling rate. CDMA phones, if they are an option would get you to 19.2k, but that is on their end, still not very fast.
The unit that the article author is speaking of is known as a "Fixed Subscriber Unit", which is rapidly becoming the choice method to replace the old Autotel and Mobitel systems. If you think it's bad now, just imagine what it was like trying to get *any* data at all over the old method of doing things. These new FSU's are quite an improvement over what was used in the past. No, Motorola isn't the only company which manufacturs FSU's, however, they are among the best. Furthermore, any other FSU by any other company will yield around the same (if not worse) results.
Your only other alternative would be to build your own network out there (either by a microwave or 802.11 longshot, or by running some of your own copper over the distance from the nearest telephone CO.) Sattelite Internet service may also be an option, although possibly expensive. At least with a FSU your only initial cost is in the capital expense, the recurring expense is just as if you had a regular cellular telephone (i.e. inexpensive.)
Speeds can't get much better over a cellular network because of all the latency involved. Just be thankful that you've got a CDMA FSU as opposed to one that uses the old-school analog AMPS. The signal's gotta go up to the shack, over the air (a great distance by the sound of it), into the cell tower, then trunk it all the way back to your ISP, where the signal gets converted. That's a lot of delay, not withstanding the sound quality factors, you're not going to get much better.
Naturally, I'm speaking of carrying an actual modem carrier over CDMA (as opposed to something like 1x, which is raw data.) Personally, I'd try to get some 802.11 longshot going, perhaps with the co-operation of your local amateur radio group, especially since you have the facilities atop the mountain already.
I know AT&T has similar plans and verizon (but verizon sucks)
Bottles.
I worked for a company in Utah that was running all of their radio broadcasts via digital signals up to the tops of mountains (much, much better transmit range). Since we were in the valley, one of our hops went from the middle of the city, off of the top of the opposite mountains, to a Gas station that had line-of-site to the top of the peak. The Gas station didn't take much to convince them into letting us stick a few medium sized yagis on the roof. BTW, none of this was 802.11b, it was all run through these deviceses called Gentner's (IIRC), which we would typically operate like they were a frame relay (they provided all of the necessary framing), but aparently some of their later models even took ethernet as an input. According to someone that used to work there, they no longer make them, so you might need to dig around on ebay. As for getting it all setup, head on down to the local AM radio station, a few hundred should get the engineers there setting you up in a hurry.
I'd really love to know, because I'm planning on signing up for their unlimited data service sometime next year, and dropping my home internet connection.
:-)
And, no, I'm not switching from Verizion, because they have been the most reliable carrier I've ever used for the locations I travel, and I've never had a billing problem with them.
Erricson F221M . I've used it before and it works well (for voice). I've used it for data, but that requires a serial cable (it acts like a modem). I would think about setting up a remote server or something. In my experience, Powertec has always been friendly and helpful. I live in the US and they have helped a few times with similar projects - they understand North American cell networks, etc.
I deployed a wireless email/voice/data solution much like this (for drilling rigs here in California) using hardware from Telular and GSM/GPRS service from T-Mobile. Telular was great to work for, and their hardware (and support) is top-notch. I wholeheartedly recommend them.
I'm talking out of my ass here, but if you could directly connect a serial link to a cell phone you would get better throughput. I can get 9.6Kbps from Fido. You would need to get some sort of serial link extender from the mountain to your terminal.
By the way, what's the closest city? Are you north of Prince Rupert?
The problems may extend further than just the converter. It may also be a weak signal, and it could be compounded by the run of cable between the two buildings.
The phone should have a data connection available as well - you might try hooking that up and running an rs-232 cable using the phone's internal modem.
But a cell phone is typically only going to give you 14.4kbps max, unless you have high speed access through one of many providers. It's a 3x speed increase, but read on...
Beyond that, I'd go back to the initial problem: Why do you need a faster than 4.8kbps connection? Turn images off the the browser. Use a lighter web interface, which most big sites now have (or news aggregators and just download RSS feeds) see Slashdot's PDA interface as an example (doesn't seem to be working right now?).
The underlying fact of the matter is that you can't type as fast than 4.8kbps, and you can't read that fast, so the only thing you are missing is visual information such as pictures. These can largely be cached. Weather forecasts can be had in text, and the satellite images are fairly small if you must download that sort of thing. Go straight to the horse's mouth to avoid all that advertising. Bookmark the direct links, and look into viewing the available pages as wml, which some desktop browsers understand (opera, I believe).
In short, there are free ways of going about this to get the same thing done. If you are sending/receiving serious amounts of data, then look into getting a satellite internet connection.
-Adam
...but I gotta say, that's one damn cool setup you've described. Kinda curious why you don't do line-of-sight radio to the top of the mountain, though. Running the wire must have cost a bundle.
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if you're using GSM, then ask if your provider can give you GPRS. it's a bodge technology, but gives roughly 56k modem speeds.
It sounds like you have 2 problems -
1. the cellular network... the 4800 limitter thing usually is for an analog phone. Since you're talking about being in a remote area, I wouldn't be surprised if the only signal you're able to get is analog. If that's the case, then 4800 is about the best you can hope to get out of it, and you don't need to worry about problem #2. (here is the black box I suspect you're using). You might try using multiple cellphones and aggregating the bandwidth.
HOWEVER, if you're able to get a digital signal up there (GSM or CDMA), then you should investigate some other options, which leads into #2. Being able to get a digital signal might involve using directional antennas and amplifiers too. Depending on how long your cable run is, you might even be able to put an antenna and an amplifier at the "top" of the mountain, and run coax further down the mountain and put an antenna there. Then you could have cellular coverage for the bottom of the mountain. Not sure about licensing requirements, but check with the people who sell em.
2. the connection between the top and bottom of the mountain - I'm not sure what "GSM Modem" you're talking about running over the phone line, but it sounds to me like you're using a regular modem and it's running over this motorola box. A better solution, assuming you can get a faster (maybe 14.4 with CDMA or 56K with GPRS/CDMA2k) would be to have one of the following at the top of the mountain:
a. an external cellular modem
b. the cellphone itself, with a data-cable
c. a computer/router with a cellular modem
With (a) or (b) you'll need some sort of serial port extender to issue AT commands to the phone/modem... Your run is too long for a regular serial cable, but they make extenders that will run over long length - possibly even using cable you've already run. With (c) you might be able to get away with using ethernet or wireless ethernet to connect to the computer up there.