On Sun, Jul 06, 2008 at 01:54:15PM -0700, michael shiloh wrote: > The Neo Freerunner is tri-band available in two versions: > > The so-called "850 MHz" version supports 850MHz, 1800MHz, and 1900MHz > The so-called "900 MHz" version supports 900MHz, 1800MHz, and 1900MHz > > As you can see, both version support 1800MHz and 1900MHz. > > The reason for these two versions is that some rural regions in the USA use > 850 MHz instead of the more-or-less world standard of 900 MHz. There may be > some rare places in the rest of the world that use 850 MHz, but for the most > part the 850 MHz version is considered the USA version, and the 900 MHz > version is suitable for just about everywhere else in the world.
No, that's not really true. The world standard for AMPS (the original cell phone system) was 800 mHz. When GSM was created it was western European only and could not interfere with AMPS phones. Since 900 mHz is a restriced band in ITU regions 1 and 3 (Europe, Africa, Asia), but not in the U.S. its users were forced off and it was given to the GSM system. In region 2 (the Americas) it is open to unlicensed low power use and Amateur radio. The major difference of over the air transmission is that AMPS used a wide FM voice channel with a seperate digital control channel, GSM used TDMA (sharing a single digital channel by giving each user a fixed time to transmit). GSM can share the same channel between control and "data" (digital voice). By the early 1990's AMPS cell phone channels had become overcrowded and there were several methods developed to alivate the problem. One was N-AMPS (narrow band FM voice) and another D-AMPS (digital AMPS similar to GSM's TDMA). In Israel Cell-Com (1993-1994?) started out with D-AMPS, Pelephone started with AMPS and switched to N-AMPS, with not much success. In the U.S. the 1900 mHz band (similar to the 1800mHz band opened in Zones 1 and 3) was opened. The lower end of the band overlaps the 1800mHz band, but some of it was already in use, so they are not the same. The 1900 mHz band was opened for PCS (Personal communications services) and almost anyone could get a PCS license (they were auctioned off) and open their own cellular phone service. The PCS cells had a very small range, so the only ones that were bought were in highly populated areas. Some PCS operators used GSM, but many did not. 1900 mHz band GSM phones are technicaly the same as 1800mHz GSM phones, with different firmware and regulatory approval. Since the U.S. market was small, there was no incentive to spend a lot of money on GSM phones for it, and there small cost of converting an 1800 mHz design to a 1900 mHz one was worth it. 1900 mHz GSM coverage peaked around the year 2000 with about 80% of the U.S. population covered, but only about 20% of the area. Meanwhile, AT&T Wireless had upgraded their 800 mHz AMPS network to D-AMPS, and they covered 100% (in reality not quite, but close enough) of the continental U.S., and most of Hawaii, and some of Alaska. In 2002 they completed a deal where Ericson would manufacture base stations compatible with their D-AMPS ones that supported mixed GSM/D-AMPS service, so they could switch one channel at a time. Nokia got the contract for their handsets. Due to the way GSM names its networks, the 800 mHz AMPS/N-AMPS/D-AMPS channels are called GSM 850. AT&T sold their cellular network and it has changed names. Now in 2008, the situation is that almost all of the U.S. (except for a few national parks, etc) is covered with the GSM 850 network that at one time belonged to AT&T Wireless (I don't know their current name), there is still the "spotty" GSM 1900 mHz coverage, and the only 1800 mHz network in zone 2 is in Brazil. In Israel, Orange's 900 mHz network coversalmost all of the terriory with from the Golan to Eilat, the Jordan river to the Med. The gaps that exist in areas controlled by the PA is due to a non competition agreement with Pal-Tel (partialy owned by Shimon Peres) and not technical reasons. When they decided to get into the high-speed data business they opened an 1800 mHz network. Due to the higher frequency, it's coverage is "spotty". In flat places, e.g. the costal plain, it works well, in hilly places, e.g. Jerusalem, high buildings and hills cause it to have "holes" in the coverage. Orange phones that are not used for data are programmed to use 900mHz first and fall back to 1800 mHz, which is why phones sold by other people may or may not work properly. They are programed the other way and don't switch to 900 mHz properly. Cell-Com has an 800 mHz D-AMPS network, and an 1800 mHz GSM network. Coverage is supposed to be good, but it still has the technical problems of 1800 mHz. I assume at some point they will convert their 800 mHz network to GSM 850, but I have no idea when or if they will abandon it due to lack of use and bandwith. I have no idea of what Pele-Phone is doing, but information would be appricated. > > If Orange uses 900 MHz as Shachar says, you should wait for the 900 MHz > version. That's an interesting question. If you use Orange near the coast, then you probably will be ok with the 850/1800/1900 version. If you plan to travel to Europe or the U.S. it should be fine as both are well covered with 1800mHz (Europe) and 850 mHz, US. (I don't know what's going on in Canada or Mexico). The 900mHz version would be better, but how much is up to speculation. I can lend anyone who wants to find out a dual band (900/1800) handset which has to manually switched so you can try one band or the other. If you use Cell-Com, then either version will work and have the same results here. If you plan to travel the world, the 900mHz version would be better, but be aware the GSM coverage is not universal and there are countries where it will not work at all. The big two I know of are Japan and Korea. It will also not work outside of big cities in the U.S. For example, New York City has GSM coverage, Albany (the NY state capital) does not. Note that when the GSM system was designed, it was illegal to take a cell phone across most international borders. The idea was for example, when you reached the French/German border, you turned in your rental car (which had a cell phone built in), took your SIM (with your phone number attached out of the cell phone), walked across the border and got into a new rental car with a different cell phone. You put your SIM in it and were back "on the air". The idea persisted, for example it was illegal to bring an Israeli cell phone into Egypt until a few years ago. I have no idea what they did if there was one built into your car and you drove there. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel [EMAIL PROTECTED] N3OWJ/4X1GM ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
