TDM
The common TDM system in the US is T-Carrier.
TDM
- Time-Division Multiplexing
STDM
- Synchronous Time-Division Multiplexing
DS0
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Level 0. One timeslot.
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A timeslot carries 8 bits.
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Frame rate is 8000 Hz. 8 × 8000 = 64 Kbps.
B8ZS
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Binary Eight Zero Substitution.
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A special way to encode
0000 0000for DS1/T1 lines.
T1 Frame
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T-Carrier, Level 1.
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Aggregates 24 DS0 frames, or 192 bits.
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The T1 gets an extra bit for framing, so 193. 193 × 8000 = 1.544 Mbps.
Super Frame
- 12 T1 frames.
Framing Search
- Each T1 frame uses the extra bit to encode part of the superframe bit pattern
0101 1101 0001, or (5, 13, 1).
APS
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Automatic Protection Switching.
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The device engaging in APS sends the data on both links, the working link and the protected link.
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The receiving device devices which to use.
DS1
- Digital Signal, Level 1.
T1
- T-Carrier, Level 1.
- Carries 24 DS0 frames, or 192 bits.
- The T1 gets an extra bit for framing, so 193. 193 × 8000 = 1.544 Mbps.
ACR
- Access Circuit Redundancy.
Cisco CEM terms
- ACR - Adaptive Clock Recovery, A technique to recovery the clock based on the fill level of the jitter buffer.
References
All you Wanted to Know about T1 But Were afraid to Ask
OCx CEM Interface Module Config Guide IOS-XE 17 ASR 900 Series