ZL50022
Data Sheet
24.3 Connection Memory High (CM_H) Bit Assignment
Connection memory high provides the detailed information required for µ-law and A-law conversion. ICL and OCL
bits describe the Input Coding Law and the Output Coding Law, respectively. They are used to select the expected
PCM coding laws for the connection, on the TDM inputs, and on the TDM outputs. The V/D bit is used to select the
class of coding law. If the V/D bit is cleared (to select a voice connection), the ICL and OCL bits select between
A-law and µ-law specifications related to G.711 voice coding. If the V/D bit is set (to select a data connection), the
ICL and OCL bits select between various bit inverting protocols. These coding laws are illustrated in the following
table. If the ICL is different than the OCL, all data bytes passing through the switch on that particular connection are
translated between the indicated laws. If the ICL and the OCL are the same, no coding law translation is performed.
The ICL, the OCL bits and V/D bit only have an effect on PCM code translations for constant delay connections,
variable delay connections and per-channel message mode.
15
0
14
0
13
0
12
0
11
0
10
0
9
0
8
0
7
0
6
0
5
0
4
3
2
1
0
V/D
ICL
1
ICL
0
OCL
1
OCL
0
Bit
Name
Description
15 - 5
Unused
Reserved
In normal functional mode, these bits MUST be set to zero.
4
V/D
Voice/Data Control
When this bit is low, the corresponding channel is for voice.
When this bit is high, the corresponding channel is for data.
3 - 2
ICL1 - 0
Input Coding Law.
Input Coding Law
ICL1-0
For Voice (V/D bit = 0)
For Data (V/D bit = 1)
00
01
10
11
CCITT.ITU A-law
CCITT.ITU µ-law
A-law w/o ABI
No code
ABI
Inverted ABI
All Bits Inverted
µ-law w/o Magnitude
Inversion
1 - 0
OCL1 - 0 Output Coding Law
Output Coding Law
OCL1-0
For Voice (V/D bit = 0)
For Data (V/D bit = 1)
00
01
10
11
CCITT.ITU A-law
CCITT.ITU µ-law
A-law w/o ABI
No code
ABI
Inverted ABI
All Bits Inverted
µ-law w/o Magnitude
Inversion
Note 1: For proper µ-law/A-law conversion, the CM_H bits should be set before Bit 15 of CM_L is set to high.
Note 2: Refer to G.711 standard for detail information of different laws.
Table 55 - Connection Memory High (CM_H) Bit Assignment
89
Zarlink Semiconductor Inc.
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
