V110 » History » Version 3
laforge, 11/20/2022 07:51 PM
| 1 | 2 | laforge | h1. ITU-T Recommendation V.110 |
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| 2 | 1 | laforge | |
| 3 | 2 | laforge | V.110 is an ITU standard for bit-rate adaptation of low-speed async serial signals (600, 1200, 2400, 4800, 7200, 9600, 12000, 14400, 19200, 24000, 28800 or 38400 bit/s) to 64 kbit/s ISDN B-channels. It was primarily used in the context of interworking between GSM Circuit Switched Data (CSD) and ISDN. |
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| 5 | h2. Details |
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| 7 | h3. Frame structure |
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| 9 | The protocol uses an 80bit (10 byte) frame. The Frame contains a frame sync pattern (similar to e.g. E1 TS0 or TRAU frames) consisting of the first byte and the first bit of every following byte. |
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| 11 | Each frame consists of |
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| 13 | * 17 bits of above-mentioned frame sync pattern plus: |
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| 14 | * 48 D-bits (D1..D48) |
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| 15 | * 7 E-bits (E1..E7) |
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| 16 | * 8 S/X-bits (S1,S3,S4,S6,S8,S9) |
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| 18 | h3. Rate Adaptation Functions |
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| 20 | h4. RA1 |
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| 22 | The rate-adaptation function RA1 converts from the V-series rates (e.g. 2400bps) to an intermediate rate of 8/16/32/64 kbit/s. |
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| 24 | h4. RA2 |
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| 26 | 3 | laforge | RA2 converts from the RA1 output rate of 8/16/32/64 kbit/s to 64 kbit/s and is actually specified in I.460 |
