2B1Q
Two-binary, one-quaternary (2B1Q) is a
.A competing encoding technique in the ISDN basic rate U interface, mainly used in Europe, is 4B3T.
Encoding
To minimize
dibits) are assigned to voltage levels according to a Gray code
, as follows:
Dibit |
Signal level |
|---|---|
| 10 | +450 mV |
| 11 | +150 mV |
| 01 | −150 mV |
| 00 | −450 mV |
If the voltage is misread as an adjacent level, this causes only a 1-bit error in the decoded data. 2B1Q code is not
DC-balanced
.
References
- ISBN 0780304403.
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| Basic line codes | ||
| Extended line codes |
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| Optical line codes |
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