XR-T6166
11
Rev. 2.03
Transmitter Code Conversion
Figure 8
shows the transmitter code conversion process
that CCITT G.703 specifies for a 64kbps codirectional
interface.
Step 1 - A 64kbps bit period is divided into four unit
intervals.
Step 2 - A binary 1 is coded as a 1100.
Step 3 - A binary 0 is coded as a 1010.
Step 4 - The binary signal is converted into a three-level
signal by alternating the polarity of consecutive blocks.
Step 5 - The alternation in polarity of the blocks is violated
every eighth block. The violation block marks the last bit
in an octet.
Bit Number
64kbps data
Steps 1-3
Step 4
Step 5
Octel Timing
Violation
Violation
10 0 1 0 0 1 1 1 0 1
1178 2 3 4 5 6 7 8
Figure 8. Transmitter Code Conversion for a 64kbps Bipolar Line Signal
