Selected Daily Notes Archive (Home Page has current notes)
Oldest (Page 1) to most new (Page 52)
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43)(44) (45)(46) (47) (48) (49) (50) (51) (52)
Is there a difference between digital cellular technology and digital PCS?
The similarity is that all modern radio-telephone service is, for the most part, cellular radio. A base station and an antenna provides coverage within a small geographical area called a cell. Networking many of those stations, called cell sites, allows roaming between the individual cells. This wireless wide area network lets a carrier provide coverage to a city or a town. Cooperative agreements with other carriers allow people to roam outside their normal coverage area. Most notably, cellular employs frequency reuse. The same set of frequencies are used over and over within a given area, to make the most economical use of the radio spectrum. No matter how the radio works, be it PCS or conventional cellular, no matter the enabling transmission technology, say TDMA or CDMA, it is all cellular radio, since distributed cell sites, employing frequency reuse, make up a wireless network.
(Just go here and it will all be explained :-) Cellular telephone basics)
PCS generally refers to cellular radio at higher frequencies. PCS is "all digital" compared to conventional cellular which is a hybrid of analog and digital routines. Being purely digital, though, is not necessarily a good thing. Quite often the all digital services lack coverage since more base stations are required. Audio quality can suffer terribly, with analog still superior. As wireless evolves the different services may operate on high and low frequencies as needed, thus blurring the defining lines between the technologies.
AT&T's IS-136 service, for example, an all digital evolution of conventional cellular, can operate on high and low frequency radio bands as needed. Depending on what the local carrier offers, it even changes its operating method, dropping back to analog cellular service where digital service isn't provided. Thus, IS-136 provides many "PCS like" services where it can, and in areas where it can't, it at least lets you talk and complete calls. I am a fan of this system.
GSM or PCS, besides being all digital, and designed in Europe with no thought of being compatible with conventional cellular systems, does differ from standard cellular in the way it makes and sends calls. The difference is in the thousands of details. But in the end it is all cellular radio.
Rockwell
Isn't this picture nice? Only Norman Rockwell could paint like that, an heroic American painter who saw good in all people, hope in all situations. If you would like to see or print out a much larger version, then do the following: 1) Click on the small image and wait. The original file is 257K. 2) Once the image is on your screen you can right click on the image, holding your cursor down on it for a few seconds. 3) A pop up window will appear, asking how you would like to save the file or link. 4) Select the option you want, it will rapidly download since the image is already cached on your hard drive. Try it, it is much easier to do than to describe. A hint for printing, resize the image by 50%, it is sometimes better to have a small file that looks good, rather than a big file which looks bad.
No Dumb Questions
There are no dumb questions at TelecomWriting.com, only opportunities to look into ideas and terms. Got this question yesterday:
Q: What is the program that a cell phone uses? And where can I get a copy ?
A: Well, actually, you can't because there isn't any. The cell phone is like a dumb computer terminal, with no intelligence built in. The exceptions are PCS and GSM phones which have SIM cards, you know, a memory module that contains some information. But that information is about the subscriber and the carrier, it's not a set of operating instructions. The cell phone instead is controlled by the nearest base station which a mobile switch supervises. That mobile switch in turn relies on network resources: landline telephone switches, carrier servers, and databases in many locations. So there isn't a cell phone program.
Mystery Phone
An Ontario reader has sent in a photograph of a mystery phone for us all to try to identify. In the above photographs you can see the guts of the phone and the outside of the case as well. Normally the bells are set on the outside as you can see by the small photograph of the Western Electric Company 1020B model. Our reader's telephone is possibly a field model, judging by the leather handle. The transmitter or receiver, possibly a candlestick, would have been connected by the wires shown. This allowed the bulky part of the phone to remain off the desktop. But if it is a field telephone then there would have been just a simple handset, not one with a base. I do not know, but if you do then give me an e-mail.
Dem Tones
I recorded a windchime two years ago. I use the sound to alert me to incoming e-mail. I find it comforting and pleasant. Don't try playing it in your browser by clicking on it. Often your browser will crash if Netscape or Explorer has a problem with the file. Or if virtual memory is on on your confuser. Instead, click on the link or right click on your selection to save it to your hard drive. When you hold your mouse button down on the link for a few seconds you'll see a pop up menu giving you a variety of ways to save the file. Make sure to save as "Source." If the file doesn't work on your hard drive, off line, then give me an e-mail. If all of this sounds too confusing then forget the whole thing, I will try writing a tutorial on sound files later. Mustn't miss out on the multi-media future!
chimes/chimes.aif: (17K) Mac users and PC users with QuickTime; Windows Media Player will not deal with this file type.
chimes/chimes.sfil (108K) Exclusive Mac format -- System 7 sound file -- put in System Folder -- Won't play on the web.
chimes/chimes.au (108K) UNIX geeks
chimes/chimes.wav (211K) All PC/ Windows 95/98/2000 users
Doraemon and the Moshimo-bokkus -- The 'What if?' Box
Doraemon is a cartoon character whose popularity in Japan ranks with the favor Mickey Mouse enjoys in America. He is a 22d century robot who looks like a blue cat without ears. Doraemon was sent back in time to help Nobita, a totally clueless fourth grader. Since Doraemon isn't too bright himself the pair manage to get into plenty of trouble. Our interest here lies with one of Doraemons' futuristic tools, the amazing Moshimo-bokkus, or 'What if?' box.
It looks like a telephone booth. If you say, for example, "What would the world be without mirrors?," the world will change to exactly that state. No more rear view mirrors on cars, nothing to help straighten ones clothes, no way to check on makeup, no man-made reflecting device of any kind. This alternative world ends when you get in the booth and say "Please go back." So you can't go back when the box is broken. And, of course, Doraemon and friends manage to break the Moshimo-bokkus quite a bit.
Although Doraemon has not been translated into English I enjoy looking at the colorful graphics about him on the web and reading about his background as a cultural icon in Japan. Doraemon is far more calm and relaxing than that maniac Pokemon stuff. The two links below are wonderful:
http://www.ex.org/4.8/35-manga_doraemon.html
You thought you knew what a star was
But you were wrong. Good grief!:
Robot Turns Sewers into Broadband Commodity
"Stream Intelligent Networks Corp. has developed a sewer robot, known as STAR (Sewer Telecommunications Access by Robot). The robot navigates through sewer systems and lays fibre-optic cables without the need for road lane closures as in traditional cable installation methods that involve digging."
Selected Daily Notes Archive (Home Page has current notes)
Oldest (Page 1) to most new (Page 52)
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43)(44) (45)(46) (47) (48) (49) (50) (51) (52)
Free Telecom Magazines through TradPub.com. Click here to go there
