XR-T6165

11

Rev. 2.02

Transmitter Code Conversion

Figure 7 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

Octet Timing

Violation

Violation

1

0

01

0

0

1

1

10

1

1

1

78

2

3

4

5

6

7

8

Figure 7. Transmitter Code Conversion for a 64kbps Bipolar Line Signal