NTAK79 2.0 Mb PRI card Page 741 of 894

The incoming serial bit stream is converted to 8-bit parallel bytes to be directed to padding control.

The signaling bits are extracted and inserted by the A07 signaling interface circuitry. The DS-30X timeslot number is mapped to the PCM-30 channel number. Timeslots 0 and 16 are currently unused for PCM.

Digital PAD

Software selects A-Law or Mu-Law and one of 32 possible PAD values for each channel. These values are provided in a PROM through which the data is routed. The idle code for A-Law is 54H and for Mu-Law is 7FH. The unequipped code is FFH for both A-Law and Mu-Law. As the idle code and unequipped code can be country dependent, the software instructs the NTAK79 to use different codes for each direction. The 32 digital pads available are listed in Table 239. The values shown are attenuation levels; 1.0 dB is 1 dB of loss and –1.0 dB is 1 dB of gain.

Table 239

Digital pad values and offset allocations (Part 1 of 2)

 

PAD SET 0

 

PAD SET 1

 

 

 

 

 

 

Offset

 

PAD

Offset

 

PAD

 

 

 

 

 

 

0

 

0.6 dB

0

 

0.0 dB

 

 

 

 

 

 

1

 

1.0 dB

1

 

–1.0 dB

 

 

 

 

 

 

2

 

2.0 dB

2

 

–2.0 dB

 

 

 

 

 

 

3

 

3.0 dB

3

 

–3.0 dB

 

 

 

 

 

 

4

 

4.0 dB

4

 

–4.0 dB

 

 

 

 

 

 

5

 

5.0 dB

5

 

–5.0 dB

 

 

 

 

 

 

6

 

6.1 dB

6

 

–6.0 dB

 

 

 

 

 

 

7

 

7.0 dB

7

 

–7.0 dB

 

 

 

 

 

 

8

 

8.0 dB

8

 

–8.0 dB

 

 

 

 

 

 

9

 

9.0 dB

9

 

–9.0 dB

 

 

 

 

 

 

Circuit Card Description and Installation

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Nortel Networks 553-3001-211 manual Digital PAD, Digital pad values and offset allocations Part 1, Pad Set
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