FEDL7041-04

OKI Semiconductor

ML7041

21/28

CR2 (PCM CODEC operating mode setting and transmit/receive gain adjustment)

B7

B6

B5

B4

B3

B2

B1

B0

CR2

TX

ON/OFF

TX GAIN2 TX GAIN1 TX GAIN0

RX

ON/OFF

RX GAIN2 RX GAIN1 RX GAIN0

Initial Value

0

0

1

1

0

0

1

1

B7 .................Transmit side PCM signal ON/OFF

0: ON 1: OFF

B6, B5, B4.....Transmit side signal gain adjustment (refer to Table 2)

B3 .................Receive side PCM signal ON/OFF

0: ON 1: OFF

B2, B1, B0.....Receive side signal gain adjustment (refer to Table 2)

Table 2 Transmit/Receive Gain Settings

B6

B5

B4

Transmit Gain

B2

B1

B0

Receive Gain

0

0

0

–6 dB

0

0

0

–12 dB

0

0

1

–4 dB

0

0

1

–9 dB

0

1

0

–2 dB

0

1

0

–6 dB

0

1

1

0 dB

0

1

1

–3 dB

1

0

0

+2 dB

1

0

0

0 dB

1

0

1

+4 dB

1

0

1

+3 dB

1

1

0

+6 dB

1

1

0

+6 dB

1

1

1

+8 dB

1

1

1

+9 dB

The above gain settings table shows the transmit/receive voice signal gain settings and the transmit side

gain settings for DTMF tones and other tones. The DTMF and other tone transmit signals are enabled

by CR4-B6, and the gain setting is referenced to the levels shown below.

DTMF tones (low group):.............................. –16 dBm0

DTMF tones (high group) and other tones: ... –14 dBm0

For example, if the transmit gain set value is set to +8 dB (B6, B5, B4) = (1,1,1), then the following tones

are output at the PCMOUT pin.

DTMF tones (low group):.............................. –8 dBm0

DTMF tones (high group) and other tones: ... –6 dBm0

Gains of the side tone (path to receive side from transmit side) and the receive side tone can be set by

register CR3.