If you are going to going to travel with a computer and a modem, you most probably will experience some connectivity problems with the local phone systems at the places you will be staying. If you have the foresight to take along a small kit in addition to your laptop and modem, you will most likely be able to get connected without trouble and without paying for a hotel electrician even if conditions are not favorable for that.
I'm not sure why (which is why this is subtitled "Hacker's Notes"), but in the hotel rooms that I stayed at in England, I found that merely purchasing a UK-to-U.S.A. style phone extension cord or adapter would not have gotten me connected by modem. If I had shown up in London with only my laptop & modem, I'm sure that I would have wasted a lot of valuable sight-seeing time and had all kinds of trouble with the phone systems and the bureaucracies of hotels.
Generally speaking, a modem needs two phone wires coming into it in order to operate. This is pretty basic, and has been true of all devices since the invention of telegraphy. Acoustic phones and modems need a carrier wave which is provided on one of the two wires. The other wire is the equivalent of the ground wire. These two wires together make up a phone line pair. With a modem and a lot of telephones, the polarity of these two wires (where it comes out of the wall-box) must be correct in order for the equipment to work. Some equipment will work no matter what the polarity of the pair of wires is; but, to my knowledge, this is not true of any modems. Also, modems and single line telephones use the middle pair of wires of a standard four-wire phone extension cord with quick-connect plugs (also known as Line 1 for two-line phone systems, Line 2 being the outer pair).
TELEPHONE EXTENSION CORDS
Before leaving home on my trip, I had packed a couple of extra telephone extension cords, with the standard U.S. style quick-connect plugs. I was pretty sure this type of cord was universal, and I wanted plenty of extension length, knowing how hotel room layouts are not always convenient to using a computer and modem. They usually install the phone beside the bed on a nightstand, and I didn't want to balance the computer on my lap to use it when there's a nice dresser and chair available for that purpose.
PHONE LINE TESTER
Almost as an afterthought, I packed a Duophone Two Line Phone Tester (available from Radio Shack), which has kept me out of trouble for years with my do-it-yourself phone line installation jobs. It is very small, has a pig-tail with a quick-connect plug, has a switch to test Line 1 or Line 2, and has a red and a green light which tells you if the wiring is (1) correct or has (2) reversed polarity or is (3) not working at all. This little device is very simple and easy to use, takes up little space, and has never failed me. I will never leave home again without it.
ADAPTER PLUGS
An adapter is necessary, in England at least, to connect the U.S. style quick-connect plug to the wall phone box. I don't know why it's different, because they do use the U.S. style plug on the other end of their extension cords, but it is; flatter and wider, with the plastic spring catch on the side rather than the front. I suspect it's different just to discourage people from installing other equipment on their lines. The first hotel I checked into was Gatwick Airport's Hilton, and they had available an adapter plug for the asking, with a twenty-five pound (about forty-dollar) deposit, in the telephone operations center in the hotel. I found it later at Tandy's (what Radio Shack is called over there) for about four pounds (about six dollars). In addition, I purchased a UK style single-to-double phone connector from Tandy, so I could have both my modem and the hotel's phone connected at the same time.
PROBLEMS AND SOLUTIONS
Once I had obtained all the necessary pieces to connect my modem to the wall plug, I tried to call AOL through one of the overseas SprintLink connections. It didn't work: the line was dead. I then tried my Phone Line Tester on it and discovered that the line wasn't dead, the line's polarity was reversed at the phone's wall socket connector. Without any tool but a pen-knife, using cellophane tape from the Reception Desk for insulation, I corrected the problem by cutting and splicing the phone extension cord I had brought with me from the U.S. I attempted a more elegant solution later on by buying a UK phone extension cord, which had the right connections on each end, but it didn't work at all because it seemed to be shorted somehow, so I used my inelegant home-spliced job throughout my trip and it worked fine. I don't know why they had the phone's polarity reversed in the hotel rooms, I ascertained that it was NOT reversed in the hotel's communication room (where they keep their fax machine). The other rooms I stayed in at other hotels also had reversed polarity; I don't know if it is convention, or an artifact of their hotel room phones, or an attempt to discourage any faxes but their own, or an accident of sloppy installation work, or some other technical reason that I don't see yet, that it is that way. All I know is, if the polarity between those two wires is correct at the modem, then my modem works. Be sure and disconnect your extension wire from the hotel's phone system and from your modem before attempting any such operation; the difference in voltage can be up to about thirty-five volts, which is high enough to be dangerous to you, and you don't want to damage either the hotel's phone system or your own equipment.
IN-LINE CONNECTORS
You can buy straight through in-line (female type) phone connectors at various places. The ones at Radio Shack keep the polarity the same when you connect two extension cords together. Others (usually the cheaper ones found at grocery stores and the like) sometimes reverse the polarity. I'm going to have one each of these connectors, one with correct polarity and one that reverses polarity, and two extension cords, next time I go on a trip. That way I won't have to cut and splice to get the correct polarity.
WHERE TO BUY ADAPTERS, TESTERS, PHONE EXTENSION CORDS, AND IN-LINE CONNECTORS
Phone adapters are available overseas at Tandy and other electronic stores, and I presume at some Radio Shack and other electronic stores stateside. Telephone company stores overseas may be of some help, although I didn't find them to be of much help (I was told if I could leave it, their engineers could fix it in a couple of weeks). Phone line testers can be bought at electronic stores and at Radio Shack. Tandy's Duophone Two Line Phone Tester is very compact, measuring only 3/4"x1-1/2"x2-1/2", about the size of a bar of hotel soap. As indicated above, extension cords and other connectors can be bought almost anywhere; electronic shops, grocery stores, drug stores, phone company stores, etc., either here or overseas.
Copyright 1994, James P. Weiler. All Rights Reserved.
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