25:
259:
a set of lower level signals. Framed E1 is designed to carry 30 or 31 E0 data channels plus 1 or 2 special channels, all other levels are designed to carry 4 signals from the level below. Because of the necessity for overhead bits, and justification bits to account for rate differences between
260:
sections of the network, each subsequent level has a capacity greater than would be expected from simply multiplying the lower level signal rate (so for example E2 is 8.448 Mbit/s and not 8.192 Mbit/s as one might expect when multiplying the E1 rate by 4).
224:(CAS) where a set of bits is used to replicate opening and closing the circuit (as if picking up the telephone receiver and pulsing digits on a rotary phone), or using tone signalling which is passed through on the voice circuits themselves. More recent systems use
216:
to be performed across all bits transmitted in each frame, to detect if the circuit is losing bits (information), but this is not always used. An alarm signal may also be transmitted using timeslot TS0. Finally, some bits are reserved for national use.
134:
263:
Note, because bit interleaving is used, it is very difficult to demultiplex low level tributaries directly, requiring equipment to individually demultiplex every single level down to the one that is required.
242:
TS0–TS31: Data traffic — Often referred to as Clear
Channel E1 or Unchannelized, it is used where no framing is required, timeslot extraction is not required and the full bandwidth (2 Mb/s) is required.
232:(SS7) where no particular timeslot is reserved for signalling purposes, the signalling protocol being transmitted on a freely chosen set of timeslots or on a different physical channel.
212:
purposes, and alternately transmits a fixed pattern. This allows the receiver to lock onto the start of each frame and match up each channel in turn. The standards allow for a full
220:
One timeslot (TS16) is often reserved for signalling purposes, to control call setup and teardown according to one of several standard telecommunications protocols. This includes
239:
TS0: Framing, TS1–TS31: Data traffic — This is named
Channelized E1, and is used where the framing is required, it allows any of the 32 timeslots to be identified and extracted.
268:
422:
142:
371:
148:(ITU-T). It was widely used in almost all countries outside the US, Canada, and Japan. E-carrier deployments have steadily been replaced by
432:
417:
325:
400:
108:
176:
peak signal is encoded with pulses using a method avoiding long periods without polarity changes. The line data rate is 2.048
184:, i.e. 2.048 Mbit/s downstream and 2.048 Mbit/s upstream) which is split into 32 timeslots, each being allocated 8
305:
252:
354:
46:
221:
197:
89:
61:
320:
130:
42:
196:, 8,000 times per second (8 × 8,000 × 32 = 2,048,000). This is ideal for voice telephone calls where the voice is
35:
295:
68:
225:
213:
165:
235:
When using E1 frames for data communication, some systems use those timeslots slightly differently, either
75:
427:
372:"Signaling System No. 7 (SS7/C7): Protocol, Architecture, and Services, Lee Dryburgh, Jeff Hewett, 2004"
209:
57:
137:(CEPT) originally standardised the E-carrier system, which revised and improved the earlier American
229:
375:
200:
at that data rate and reconstructed at the other end. The timeslots are numbered from 0 to 31.
284:
279:
358:
193:
126:
82:
411:
351:
331:
300:
256:
181:
24:
401:
Signaling System No. 7 (SS7/C7): Protocol, Architecture, and
Services eBook
315:
138:
129:
developed for digital transmission of many simultaneous telephone calls by
149:
169:
255:
based on the E0 signal rate is designed so that each higher level can
177:
153:
135:
European
Conference of Postal and Telecommunications Administrations
310:
145:
289:
173:
189:
185:
18:
164:
An E1 link operates over two separate sets of wires, usually
188:
in turn. Thus each timeslot sends and receives an 8-bit
16:
Telephone transmission carrier system used outside US
49:. Unsourced material may be challenged and removed.
152:as telecommunication networks transition towards
141:technology, and this has now been adopted by the
361:, RAD data communications University Tutorials
328:- discussion of practical telephone switches.
269:Comparison of T-carrier and E-carrier systems
8:
109:Learn how and when to remove this message
334:- the mathematics of telephone switches.
146:Telecommunication Standardization Sector
344:
192:sample, usually encoded according to
143:International Telecommunication Union
7:
47:adding citations to reliable sources
326:Nonblocking minimal spanning switch
208:One timeslot (TS0) is reserved for
14:
306:Plesiochronous Digital Hierarchy
172:(unbalanced cable). A nominal 3
23:
34:needs additional citations for
1:
125:is a member of the series of
423:Telecommunications standards
222:channel-associated signaling
433:Telecommunication protocols
418:Computer network technology
449:
321:Time-division multiplexing
285:Digital Signal 1 (DS1, T1)
266:
168:(balanced cable) or using
131:time-division multiplexing
296:List of device bandwidths
226:common-channel signaling
214:cyclic redundancy check
166:unshielded twisted pair
43:improve this article
230:Signalling System 7
357:2013-10-14 at the
160:E1 frame structure
378:on 1 January 2012
204:Special timeslots
119:
118:
111:
93:
440:
388:
387:
385:
383:
374:. Archived from
368:
362:
349:
247:Hierarchy levels
114:
107:
103:
100:
94:
92:
51:
27:
19:
448:
447:
443:
442:
441:
439:
438:
437:
408:
407:
397:
392:
391:
381:
379:
370:
369:
365:
359:Wayback Machine
350:
346:
341:
292:encoding scheme
276:
271:
249:
206:
194:A-law algorithm
162:
127:carrier systems
115:
104:
98:
95:
52:
50:
40:
28:
17:
12:
11:
5:
446:
444:
436:
435:
430:
425:
420:
410:
409:
404:
403:
396:
395:External links
393:
390:
389:
363:
352:E1 Environment
343:
342:
340:
337:
336:
335:
329:
323:
318:
313:
308:
303:
298:
293:
287:
282:
275:
272:
248:
245:
244:
243:
240:
205:
202:
161:
158:
117:
116:
99:September 2016
31:
29:
22:
15:
13:
10:
9:
6:
4:
3:
2:
445:
434:
431:
429:
426:
424:
421:
419:
416:
415:
413:
406:
402:
399:
398:
394:
377:
373:
367:
364:
360:
356:
353:
348:
345:
338:
333:
330:
327:
324:
322:
319:
317:
314:
312:
309:
307:
304:
302:
299:
297:
294:
291:
288:
286:
283:
281:
278:
277:
273:
270:
265:
261:
258:
254:
246:
241:
238:
237:
236:
233:
231:
227:
223:
218:
215:
211:
203:
201:
199:
195:
191:
187:
183:
179:
175:
171:
167:
159:
157:
155:
151:
147:
144:
140:
136:
132:
128:
124:
113:
110:
102:
91:
88:
84:
81:
77:
74:
70:
67:
63:
60: –
59:
55:
54:Find sources:
48:
44:
38:
37:
32:This article
30:
26:
21:
20:
428:Multiplexing
405:
380:. Retrieved
376:the original
366:
347:
332:Clos network
301:Multiplexing
262:
250:
234:
219:
207:
163:
122:
120:
105:
96:
86:
79:
72:
65:
53:
41:Please help
36:verification
33:
228:(CCS) such
182:full duplex
58:"E-carrier"
412:Categories
339:References
267:See also:
69:newspapers
316:T-carrier
280:D 0 (DS0)
257:multiplex
139:T-carrier
123:E-carrier
355:Archived
274:See also
150:Ethernet
210:framing
198:sampled
170:coaxial
83:scholar
382:26 May
178:Mbit/s
154:all IP
133:. The
85:
78:
71:
64:
56:
311:STM-1
90:JSTOR
76:books
384:2010
290:HDB3
251:The
186:bits
174:volt
121:The
62:news
253:PDH
190:PCM
45:by
414::
156:.
386:.
180:(
112:)
106:(
101:)
97:(
87:·
80:·
73:·
66:·
39:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
