larry@uunet.uu.net (Larry Lippman) (10/16/89)
In article <telecom-v09i0445m05@vector.dallas.tx.us> gentry@kcdev.uucp (Art Gentry) writes: > We use repeaters, spaced anywhere from 1 to 30 miles, depending on the > type of carrier technology. These repeaters are powered by DC current > carried down the same pairs of the transmission. Each direction takes > one pair, one for the E->W and the other for W->E (no, I'm sorry, but > AT&T does not go N->S or S->N <smile>) Actually, all repeaters will > show an East/West transmission, just to keep things easy. The E/W designation on repeaters is carried over from the early days of telegraphic communication where the concept of a "repeater" originated, although in those days repeaters were of the relay-variety for morse code traffic. Most long telegraphic routes were in fact East-West in direction, and the arbitrary designation of E/W for the ends of a repeater remained throughout the telegraph era into that of the telephone. Also, lest someone feel that the concept of a PCM regenerator is *new*, consider that the morse telegraphic systems were in fact both digital and PCM, and thus such PCM regenerators were in use over 150 years ago! Furthermore, some of the early telegraphic systems, especially those used with submarine cable, were in fact bipolar in nature - not unlike that of a T1 line, although admittedly the data rates were a bit slower than 1.544 megabits/sec. :-) <> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp. <> UUCP {allegra|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> TEL 716/688-1231 | 716/773-1700 {hplabs|utzoo|uunet}!/ \uniquex!larry <> FAX 716/741-9635 | 716/773-2488 "Have you hugged your cat today?"