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DS21Q55

14. DS0 MONITORING FUNCTION

The DS21Q55 has the ability to monitor one DS0 64kbps channel in the transmit direction and one DS0 channel in the receive direction at the same time. In the transmit direction the user will determine which channel is to be monitored by properly setting the TCM0 to TCM4 bits in the TDS0SEL register. In the receive direction, the RCM0 to RCM4 bits in the RDS0SEL register need to be properly set. The DS0 channel pointed to by the TCM0 to TCM4 bits will appear in the transmit DS0 monitor (TDS0M) register and the DS0 channel pointed to by the RCM0 to RCM4 bits will appear in the receive DS0 (RDS0M) register. The TCM4 to TCM0 and RCM4 to RCM0 bits should be programmed with the decimal decode of the appropriate T1 or E1 channel. T1 channels 1 through 24 map to register values 0 through 23. E1 channels 1 through 32 map to register values 0 through 31. For example, if DS0 channel 6 in the transmit direction and DS0 channel 15 in the receive direction needed to be monitored, then the following values would be programmed into TDS0SEL and RDS0SEL:

TCM4 = 0

RCM4 = 0

TCM3 = 0

RCM3 = 1

TCM2 = 1

RCM2 = 1

TCM1 = 0

RCM1 = 1

TCM0 = 1

RCM0 = 0

14.1 Transmit DS0 Monitor Registers

Register Name:

TDS0SEL

Register Description:

Transmit Channel Monitor Select

Register Address:

74h

Bit #

Name

Default

7

6

5

4

3

2

1

0

-

-

-

TCM4

TCM3

TCM2

TCM1

TCM0

0

0

0

0

0

0

0

0

Bits 0 to 4 Transmit Channel Monitor Bits (TCM0 to TCM4). TCM0 is the LSB of a 5 -bit channel select that determines which transmit channel data will appear in the TDS0M register.

Bits 5 to 7/Unused, must be set to zero for proper operation.

Register Name:

TDS0M

Register Description:

Transmit DS0 Monitor Register

Register Address:

75h

Bit #

Name

Default

7

6

5

4

3

2

1

0

B1

B2

B3

B4

B5

B6

B7

B8

0

0

0

0

0

0

0

0

Bits 0 to 7/Transmit DS0 Channel Bits (B1 to B8). Transmit channel data that has been selected by the transmit channel monitor select register. B8 is the LSB of the DS0 channel (last bit to be transmitted).

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Please contact telecom.support@dalsemi.com or search http://www.maxim-ic.com for updated

information.

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Maxim DS21Q55 specifications 14. DS0 Monitoring Function, Transmit DS0 Monitor Registers, TDS0SEL, TDS0M