230:
341:
another extension, the operator places the front cord in the associated jack and pulls the front key backwards to ring the called party. After connecting, the operator leaves both cords "up" with the keys in the normal position so the parties can converse. The supervision lamps light to alert the operator when the parties finish their conversation and go on-hook. Either party could "flash" the operator's supervision lamps by depressing their switch hook for a second and releasing it, in case they needed assistance with a problem. When the operator pulls down a cord, a pulley weight behind the switchboard pulls it down to prevent it from tangling.
151:
20:
286:
97:
1555:
226:
would try alternate routings through intermediate cities. The operator would plug into a trunk for the destination city, and the inward operator would answer. The inward operator would obtain the number from the local information operator and ring the call. Once the called party answered, the originating operator would advise him or her to stand by for the calling party, whom she'd then ring back, and record the starting time once the conversation began.
1565:
1544:
1575:
254:(a fast busy signal), it could indicate "all circuits busy," or a problem in the destination exchange. The operator might be able to use a different routing to complete the call. If the operator could not get through by dialing the number, she could call the inward operator in the destination city, and ask her to try the number, or to test a line to see if it was busy or out of order.
261:(TSPS) and similar systems, which greatly reduced operator involvement in calls. The customer would, instead of simply dialing "0" for the operator, dial 1+NPA+7digits, after which an operator would answer and provide the desired service (coin collection, obtaining acceptance on a collect call, etc.), and then release the call to be automatically handled by the TSPS.
325:. Each of the keys has three positions: back, normal and forward. When a key is in the normal position an electrical talk path connects the front and rear cords. A key in the forward position (front key) connects the operator to the cord pair, and a key in the back position sends a ring signal out on the cord (on older manual exchanges). Each cord has a three-wire
225:
The long-distance operator would record the name and city of the person to be called, and the operator would advise the calling party to hang up and wait for the call to be completed. Each toll center had only a limited number of trunks to distant cities, and if those circuits were busy, the operator
268:
In the mid-1980s the Bell
Operating Companies (BOCs) opened their own Operator Services offices with a system called TOPS (Traffic Operator Position System) to act as local and intraLATA telephone operators. With this the BOCs took intraLATA call traffic from AT&T as well as services which were
204:
devised the
Divided Multiple Switchboard for operators to work together, with a team on the "A board" and another on the "B". These operators were almost always women until the early 1970s, when men were once again hired. Cord switchboards were often referred to as "cordboards" by telephone company
199:
Early switchboards in large cities usually were mounted floor to ceiling in order to allow the operators to reach all the lines in the exchange. The operators were boys who would use a ladder to connect to the higher jacks. Late in the 1890s this measure failed to keep up with the increasing number
276:
As technology changed, so did the application of
Interflow. Interflow was implemented nationwide by AT&T. This allowed AT&T to close virtually every operator office throughout the US. As of 2004 the only AT&T operator offices remaining were located in Houston, Texas, and Jacksonville,
272:
In the early 1990s AT&T replaced TSPS with OSPS (Operator
Service Position System). The OSPS position was a computer terminal which the AT&T operator entered billing information. With the advent of OSPS a feature called Interflow allowed operators on a system to answer calls from anywhere
179:
In
January 1878 the Boston Telephone Dispatch company had started hiring boys as telephone operators. Boys had been very successful as telegraphy operators, but their attitude, lack of patience, and behavior was unacceptable for live telephone contact, so the company began hiring women operators
264:
Before the late 1970s and early 1980s, it was common for many smaller cities to have their own operators. An NPA (area code) would usually have its largest city as its primary toll center, with smaller toll centers serving the secondary cities scattered throughout the NPA. TSPS allowed telephone
245:
operator dialing, the operator would plug into a tandem trunk and dial the NPA (area code) and operator code for the information operator in the distant city. For instance, the New York City information operator was 212-131. If the customer knew the number, and the point was direct-dialable, the
249:
In the 1960s, once most phone subscribers had direct long-distance dialing, a single type of operator began to serve both the local and long-distance functions. A customer might call to request a collect call, a call billed to a third number, or a person-to-person call. All toll calls from coin
340:
When a call is received, a jack lamp lights on the back panel and the operator responds by placing the rear cord into the corresponding jack and throwing the front key forward. The operator then converses with the caller, who informs the operator to whom he or she would like to speak. If it is
352:
signals must pass in both directions. In a one-way trunk, the originating or A board sends a short for off-hook, and an open for on-hook, while the terminating or B board sends normal polarity or reverse polarity. This "reverse battery" signaling was carried over to later automatic exchanges.
176:, installed the first central office and switchboard that served both as a security service at night for banks and businesses, as well as a telephone system. The switchboard operated telephone instruments manufactured by Charles Williams, a licensee of the Alexander Graham Bell company.
316:
On the table or desk area in front of the operator are columns of 3-position toggle switches termed "keys", lamps, and cords. Each column consists of a front key and a rear key, a front lamp and a rear lamp, followed by a front cord and a rear cord, making up together a
164:
Following the invention of the telephone in 1876, the first telephones were rented in pairs which were limited to conversation between the parties operating those two instruments. The use of a central exchange was soon found to be even more advantageous than in
376:
area required special billing arrangements to allow the rate for a local call to vary based on the distance called. In less densely populated regions, calls from payphones were handled by normal assistance operators without the use of dedicated coin boards.
321:. The front key is the "talk" key allowing the operator to speak with that particular cord pair. The rear key on older "manual" boards and PBXs is used to ring a telephone physically. On newer boards, the back key is used to collect (retrieve) money from
308:
The switchboard is usually designed to accommodate the operator, who sits facing it. It has a high back panel, which consists of rows of female jacks, each jack designated and wired as a local extension of the switchboard (which serves an individual
221:
operator in order to place a toll call. In large cities, there was often a special number, such as 112, which would ring the long-distance operator directly. Elsewhere, the subscriber would ask the local operator to ring the long-distance operator.
209:
and other automated switching systems first eliminated the "B" operator and then, usually years later, the "A". Rural and suburban switchboards for the most part remained small and simple. In many cases, customers knew their operator by name.
246:
operator would dial the call. If the distant city did not have dialable numbers, the operator would dial the code for the inward operator serving the called party, and ask her to ring the number.
250:
phones required operator assistance. The operator was also available to help complete a local or long-distance number which did not complete. For example, if a customer encountered a
184:
as the first woman operator. Small towns typically had the switchboard installed in the operator's home so that he or she could answer calls on a 24-hour basis. In 1894,
269:
once provided on a cordboard (Toll
Stations, Mobile and Marine ). Operators from AT&T returned to work for the BOC as the intraLATA traffic was cut to the BOC.
217:) service, switchboards continued to serve specialized purposes. Before the advent of direct-dialed long-distance calls, a subscriber would need to contact the
64:
Nevertheless, many manual branch exchanges remained operational into the second half of the 20th century in many enterprises. Some establishments, such as the
819:
265:
companies to close smaller toll centers and consolidate operator services in regional centers which might be hundreds of miles from the subscriber.
107:
1527:
1499:
1494:
519:
443:
185:
483:
364:, these "coin boards" were gradually phased out after the introduction of the Automated Coin Toll System that was provided by the
229:
201:
1599:
1521:
1516:
1506:
1486:
1288:
653:
1578:
1511:
1357:
1283:
386:
1377:
137:
1162:
710:
512:
1273:
365:
258:
1268:
1293:
1604:
1568:
1329:
1226:
769:
564:
536:
54:
1558:
1065:
505:
1417:
1339:
1278:
985:
119:
71:
Electronic devices and computer technology have given exchange operators more features. For example, a
1189:
1150:
995:
895:
824:
757:
584:
419:
1548:
790:
725:
678:
638:
193:
1387:
1372:
1216:
1167:
1090:
990:
668:
554:
549:
326:
289:
214:
173:
72:
451:
1309:
1095:
910:
855:
850:
663:
628:
115:
1211:
1015:
980:
900:
880:
802:
690:
611:
297:
293:
218:
189:
544:
150:
1125:
1085:
1055:
812:
747:
569:
44:
39:
between users or other switchboards. The switchboard is an essential component of a manual
19:
8:
1135:
1075:
834:
796:
594:
579:
477:
61:
in 1888, has replaced most switchboards in central telephone exchanges around the world.
50:
The switchboard saw the peak of its use in the 20th century before wider adoption of the
491:
1362:
1319:
1250:
1120:
1050:
1025:
960:
807:
528:
172:
In May 1877, the Holmes
Burglar Alarm Company in Boston, Massachusetts, established by
40:
368:. Dedicated coin boards were primarily used in large, densely populated areas such as
1402:
1324:
1238:
1221:
1184:
1030:
860:
829:
695:
589:
313:) or as an incoming or outgoing trunk line. The jack is also associated with a lamp.
51:
1070:
1407:
1367:
1347:
1314:
1243:
1201:
1115:
970:
955:
930:
905:
865:
715:
574:
559:
257:
Cord switchboards used for these purposes were replaced in the 1970s and 1980s by
1035:
890:
658:
633:
621:
285:
242:
1233:
1105:
1080:
1040:
1010:
885:
720:
673:
648:
606:
80:
58:
36:
1593:
1382:
1155:
1145:
1060:
950:
945:
935:
920:
742:
601:
369:
361:
1260:
1100:
1045:
975:
940:
875:
774:
764:
616:
330:
318:
251:
206:
16:
Device used to connect telephone circuits to establish calls between users
1460:
1110:
1020:
1005:
965:
925:
784:
334:
234:
65:
1465:
1172:
870:
779:
735:
705:
683:
373:
310:
166:
1450:
915:
730:
497:
181:
180:
instead. Thus, on
September 1, 1878, Boston Telephone Dispatch hired
32:
1445:
1435:
1352:
1177:
1000:
357:
349:
322:
301:
76:
47:
who use electrical cords or switches to establish the connections.
1440:
1425:
643:
345:
476:
292:
operator works a switchboard in the underground command post at
1470:
1430:
752:
356:
Some areas used specialized switchboards to handle calls from
1455:
1392:
700:
106:
deal primarily with the United States and do not represent a
1397:
492:
Atlanta
Telephone History: Part 1 - Early Telephone Service
407:
The First
Telephone Switchboard and Its Method of Operation
409:, Bell Telephone Quarterly Volume 9(3), p.205 (July 1930).
487:. Vol. 26 (11th ed.). 1911. pp. 547–557.
333:
for testing, ringing and voice; and a sleeve wire for
444:"Telephone History: AT&T's First Male Operator"
1591:
241:In the 1940s, with the advent of dial pulse and
213:As telephone exchanges converted to automatic (
513:
104:The examples and perspective in this section
1528:Global telecommunications regulation bodies
186:New England Telephone and Telegraph Company
1564:
520:
506:
122:, or create a new section, as appropriate.
138:Learn how and when to remove this message
420:"PBS American Experience, The Telephone"
284:
228:
149:
79:usually has an attendant console, or an
31:is a device used to connect circuits of
18:
83:function, which bypasses the operator.
1592:
527:
192:-operated switchboard on January 9 in
57:. The automatic exchange, invented by
501:
1574:
494:especially the section from 1905 on.
90:
13:
469:
412:
387:Telephone in United States history
14:
1616:
237:international switchboard in 1943
1573:
1563:
1554:
1553:
1542:
1163:Free-space optical communication
95:
366:Traffic Service Position System
259:Traffic Service Position System
68:, still operate a switchboard.
436:
399:
1:
1600:History of telecommunications
392:
155:
1549:Telecommunication portal
1330:Telecommunications equipment
280:
55:automatic telephone exchange
7:
1066:Alexander Stepanovich Popov
380:
118:, discuss the issue on the
10:
1621:
770:Telecommunications history
405:G.K. Thompson, R.B. Hill,
205:personnel. Conversion to
86:
1537:
1479:
1416:
1378:Public Switched Telephone
1338:
1302:
1259:
1200:
1190:telecommunication circuit
1151:Fiber-optic communication
1134:
896:Francis Blake (telephone)
843:
691:Optical telecommunication
535:
1289:Orbital angular-momentum
726:Satellite communications
565:Communications satellite
194:Lexington, Massachusetts
1168:Molecular communication
991:Gardiner Greene Hubbard
820:Undersea telegraph line
555:Cable protection system
484:Encyclopædia Britannica
73:private branch exchange
1310:Communication protocol
1096:Charles Sumner Tainter
911:Walter Houser Brattain
856:Edwin Howard Armstrong
664:Information revolution
305:
238:
161:
24:
1284:Polarization-division
1016:Narinder Singh Kapany
981:Erna Schneider Hoover
901:Jagadish Chandra Bose
881:Alexander Graham Bell
612:online video platform
298:Offutt Air Force Base
294:Strategic Air Command
288:
273:within their region.
232:
153:
45:switchboard operators
43:, and is operated by
29:telephone switchboard
23:PBX switchboard, 1975
22:
1126:Vladimir K. Zworykin
1086:Almon Brown Strowger
1056:Charles Grafton Page
711:Prepaid mobile phone
639:Electrical telegraph
188:installed the first
154:Telephone operator,
116:improve this section
1605:Telephone exchanges
1076:Johann Philipp Reis
835:Wireless revolution
797:The Telephone Cases
654:Hydraulic telegraph
327:TRS phone connector
1274:Frequency-division
1251:Telephone exchange
1121:Charles Wheatstone
1051:Jun-ichi Nishizawa
1026:Innocenzo Manzetti
961:Reginald Fessenden
696:Optical telegraphy
529:Telecommunications
306:
239:
162:
41:telephone exchange
25:
1587:
1586:
1325:Store and forward
1320:Data transmission
1234:Network switching
1185:Transmission line
1031:Guglielmo Marconi
996:Internet pioneers
861:Mohamed M. Atalla
830:Whistled language
478:"Telephone"
148:
147:
140:
52:electromechanical
1612:
1577:
1576:
1567:
1566:
1557:
1556:
1547:
1546:
1545:
1418:Notable networks
1408:Wireless network
1348:Cellular network
1340:Types of network
1315:Computer network
1202:Network topology
1116:Thomas A. Watson
971:Oliver Heaviside
956:Philo Farnsworth
931:Daniel Davis Jr.
906:Charles Bourseul
866:John Logie Baird
575:Data compression
570:Computer network
522:
515:
508:
499:
498:
488:
480:
463:
462:
460:
459:
450:. Archived from
440:
434:
433:
431:
430:
416:
410:
403:
372:where the large
160:
157:
143:
136:
132:
129:
123:
99:
98:
91:
1620:
1619:
1615:
1614:
1613:
1611:
1610:
1609:
1590:
1589:
1588:
1583:
1543:
1541:
1533:
1475:
1412:
1334:
1298:
1255:
1204:
1196:
1137:
1130:
1036:Robert Metcalfe
891:Tim Berners-Lee
839:
659:Information Age
531:
526:
475:
472:
470:Further reading
467:
466:
457:
455:
448:PrivateLine.com
442:
441:
437:
428:
426:
418:
417:
413:
404:
400:
395:
383:
323:coin telephones
283:
243:multi-frequency
202:Milo G. Kellogg
174:Edwin T. Holmes
158:
144:
133:
127:
124:
113:
100:
96:
89:
37:telephone calls
17:
12:
11:
5:
1618:
1608:
1607:
1602:
1585:
1584:
1582:
1581:
1571:
1561:
1551:
1538:
1535:
1534:
1532:
1531:
1524:
1519:
1514:
1509:
1504:
1503:
1502:
1497:
1489:
1483:
1481:
1477:
1476:
1474:
1473:
1468:
1463:
1458:
1453:
1448:
1443:
1438:
1433:
1428:
1422:
1420:
1414:
1413:
1411:
1410:
1405:
1400:
1395:
1390:
1385:
1380:
1375:
1370:
1365:
1360:
1355:
1350:
1344:
1342:
1336:
1335:
1333:
1332:
1327:
1322:
1317:
1312:
1306:
1304:
1300:
1299:
1297:
1296:
1291:
1286:
1281:
1276:
1271:
1269:Space-division
1265:
1263:
1257:
1256:
1254:
1253:
1248:
1247:
1246:
1241:
1231:
1230:
1229:
1219:
1214:
1208:
1206:
1198:
1197:
1195:
1194:
1193:
1192:
1182:
1181:
1180:
1170:
1165:
1160:
1159:
1158:
1148:
1142:
1140:
1132:
1131:
1129:
1128:
1123:
1118:
1113:
1108:
1106:Camille Tissot
1103:
1098:
1093:
1088:
1083:
1081:Claude Shannon
1078:
1073:
1071:Tivadar Puskás
1068:
1063:
1058:
1053:
1048:
1043:
1041:Antonio Meucci
1038:
1033:
1028:
1023:
1018:
1013:
1011:Charles K. Kao
1008:
1003:
998:
993:
988:
986:Harold Hopkins
983:
978:
973:
968:
963:
958:
953:
948:
943:
938:
933:
928:
923:
918:
913:
908:
903:
898:
893:
888:
886:Emile Berliner
883:
878:
873:
868:
863:
858:
853:
847:
845:
841:
840:
838:
837:
832:
827:
825:Videotelephony
822:
817:
816:
815:
810:
800:
793:
788:
782:
777:
772:
767:
762:
761:
760:
755:
750:
740:
739:
738:
728:
723:
721:Radiotelephone
718:
713:
708:
703:
698:
693:
688:
687:
686:
676:
671:
666:
661:
656:
651:
646:
641:
636:
631:
626:
625:
624:
619:
614:
609:
607:Internet video
599:
598:
597:
592:
587:
582:
572:
567:
562:
557:
552:
547:
541:
539:
533:
532:
525:
524:
517:
510:
502:
496:
495:
489:
471:
468:
465:
464:
435:
411:
397:
396:
394:
391:
390:
389:
382:
379:
296:headquarters,
290:U.S. Air Force
282:
279:
200:of lines, and
146:
145:
110:of the subject
108:worldwide view
103:
101:
94:
88:
85:
81:auto-attendant
59:Almon Strowger
15:
9:
6:
4:
3:
2:
1617:
1606:
1603:
1601:
1598:
1597:
1595:
1580:
1572:
1570:
1562:
1560:
1552:
1550:
1540:
1539:
1536:
1529:
1525:
1523:
1520:
1518:
1515:
1513:
1510:
1508:
1505:
1501:
1498:
1496:
1493:
1492:
1490:
1488:
1485:
1484:
1482:
1478:
1472:
1469:
1467:
1464:
1462:
1459:
1457:
1454:
1452:
1449:
1447:
1444:
1442:
1439:
1437:
1434:
1432:
1429:
1427:
1424:
1423:
1421:
1419:
1415:
1409:
1406:
1404:
1401:
1399:
1396:
1394:
1391:
1389:
1386:
1384:
1381:
1379:
1376:
1374:
1371:
1369:
1366:
1364:
1361:
1359:
1356:
1354:
1351:
1349:
1346:
1345:
1343:
1341:
1337:
1331:
1328:
1326:
1323:
1321:
1318:
1316:
1313:
1311:
1308:
1307:
1305:
1301:
1295:
1294:Code-division
1292:
1290:
1287:
1285:
1282:
1280:
1279:Time-division
1277:
1275:
1272:
1270:
1267:
1266:
1264:
1262:
1258:
1252:
1249:
1245:
1242:
1240:
1237:
1236:
1235:
1232:
1228:
1225:
1224:
1223:
1220:
1218:
1215:
1213:
1210:
1209:
1207:
1205:and switching
1203:
1199:
1191:
1188:
1187:
1186:
1183:
1179:
1176:
1175:
1174:
1171:
1169:
1166:
1164:
1161:
1157:
1156:optical fiber
1154:
1153:
1152:
1149:
1147:
1146:Coaxial cable
1144:
1143:
1141:
1139:
1133:
1127:
1124:
1122:
1119:
1117:
1114:
1112:
1109:
1107:
1104:
1102:
1099:
1097:
1094:
1092:
1089:
1087:
1084:
1082:
1079:
1077:
1074:
1072:
1069:
1067:
1064:
1062:
1061:Radia Perlman
1059:
1057:
1054:
1052:
1049:
1047:
1044:
1042:
1039:
1037:
1034:
1032:
1029:
1027:
1024:
1022:
1019:
1017:
1014:
1012:
1009:
1007:
1004:
1002:
999:
997:
994:
992:
989:
987:
984:
982:
979:
977:
974:
972:
969:
967:
964:
962:
959:
957:
954:
952:
951:Lee de Forest
949:
947:
946:Thomas Edison
944:
942:
939:
937:
936:Donald Davies
934:
932:
929:
927:
924:
922:
921:Claude Chappe
919:
917:
914:
912:
909:
907:
904:
902:
899:
897:
894:
892:
889:
887:
884:
882:
879:
877:
874:
872:
869:
867:
864:
862:
859:
857:
854:
852:
849:
848:
846:
842:
836:
833:
831:
828:
826:
823:
821:
818:
814:
811:
809:
806:
805:
804:
801:
799:
798:
794:
792:
789:
786:
783:
781:
778:
776:
773:
771:
768:
766:
765:Smoke signals
763:
759:
756:
754:
751:
749:
746:
745:
744:
743:Semiconductor
741:
737:
734:
733:
732:
729:
727:
724:
722:
719:
717:
714:
712:
709:
707:
704:
702:
699:
697:
694:
692:
689:
685:
682:
681:
680:
677:
675:
672:
670:
667:
665:
662:
660:
657:
655:
652:
650:
647:
645:
642:
640:
637:
635:
632:
630:
627:
623:
620:
618:
615:
613:
610:
608:
605:
604:
603:
602:Digital media
600:
596:
593:
591:
588:
586:
583:
581:
578:
577:
576:
573:
571:
568:
566:
563:
561:
558:
556:
553:
551:
548:
546:
543:
542:
540:
538:
534:
530:
523:
518:
516:
511:
509:
504:
503:
500:
493:
490:
486:
485:
479:
474:
473:
454:on 2013-03-12
453:
449:
445:
439:
425:
421:
415:
408:
402:
398:
388:
385:
384:
378:
375:
374:local calling
371:
370:New York City
367:
363:
362:North America
359:
354:
351:
347:
342:
338:
336:
332:
328:
324:
320:
314:
312:
303:
299:
295:
291:
287:
278:
274:
270:
266:
262:
260:
255:
253:
247:
244:
236:
231:
227:
223:
220:
219:long-distance
216:
211:
208:
203:
197:
195:
191:
187:
183:
177:
175:
170:
168:
152:
142:
139:
131:
121:
117:
111:
109:
102:
93:
92:
84:
82:
78:
74:
69:
67:
62:
60:
56:
53:
48:
46:
42:
38:
35:to establish
34:
30:
21:
1261:Multiplexing
1136:Transmission
1101:Nikola Tesla
1091:Henry Sutton
1046:Samuel Morse
976:Robert Hooke
941:Amos Dolbear
876:John Bardeen
795:
775:Telautograph
679:Mobile phone
634:Edholm's law
617:social media
550:Broadcasting
482:
456:. Retrieved
452:the original
447:
438:
427:. Retrieved
423:
414:
406:
401:
355:
344:On a trunk,
343:
339:
335:busy signals
331:tip and ring
319:cord circuit
315:
307:
275:
271:
267:
263:
256:
252:reorder tone
248:
240:
224:
212:
207:panel switch
198:
178:
171:
163:
134:
125:
105:
70:
63:
49:
28:
26:
1461:NPL network
1173:Radio waves
1111:Alfred Vail
1021:Hedy Lamarr
1006:Dawon Kahng
966:Elisha Gray
926:Yogen Dalal
851:Nasir Ahmed
785:Teleprinter
649:Heliographs
235:Bell System
159: 1900
75:(PBX) in a
66:White House
1594:Categories
1507:Antarctica
1466:Toasternet
1388:Television
871:Paul Baran
803:Television
787:(teletype)
780:Telegraphy
758:transistor
736:Phryctoria
706:Photophone
684:Smartphone
674:Mass media
458:2013-09-18
429:2013-08-24
393:References
311:subscriber
167:telegraphy
33:telephones
1491:Americas
1480:Locations
1451:Internet2
1212:Bandwidth
916:Vint Cerf
813:streaming
791:Telephone
731:Semaphore
622:streaming
358:payphones
281:Operation
277:Florida.
182:Emma Nutt
128:June 2022
120:talk page
1559:Category
1446:Internet
1436:CYCLADES
1353:Ethernet
1303:Concepts
1227:terminal
1178:wireless
1001:Bob Kahn
844:Pioneers
669:Internet
560:Cable TV
381:See also
350:off-hook
304:in 1967.
302:Nebraska
233:A large
114:You may
77:business
1579:Commons
1569:Outline
1522:Oceania
1441:FidoNet
1426:ARPANET
1239:circuit
808:digital
537:History
424:PBS.org
346:on-hook
190:battery
87:History
1517:Europe
1487:Africa
1471:Usenet
1431:BITNET
1368:Mobile
1244:packet
753:MOSFET
748:device
545:Beacon
1500:South
1495:North
1456:JANET
1393:Telex
1383:Radio
1222:Nodes
1217:Links
1138:media
716:Radio
701:Pager
629:Drums
595:video
590:image
580:audio
360:. In
1512:Asia
1398:UUCP
1358:ISDN
348:and
215:dial
1403:WAN
1373:NGN
1363:LAN
644:Fax
585:DCT
1596::
481:.
446:.
422:.
337:.
329::
300:,
196:.
169:.
156:c.
27:A
1530:)
1526:(
521:e
514:t
507:v
461:.
432:.
141:)
135:(
130:)
126:(
112:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
.jpg)