Silicon Laboratories SI2493/57/34/15/04 - Manual (Page 196)

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196 Rev. 1.3
7.5. Handset
7.5.1. Overview
This mode uses the voice pass-through connection to route SSI data between the Si3000 and the DAA. The
modem remains in AT command mode and provides V.253 event notifications. The host controller is responsible
for detecting the status of the handset position. The following sections provides detailed examples of originating
and answering a voice call with the handset.
7.5.2. Handset Configuration
Table 120 contains the initial configuration that is used by all dialing use cases. The sequence is also sent for the
answer case. The user will have been notified of the incoming call through a local +VTS ring tone and a raised
handset event would prompt the Handset Configuration sequence to answer the call. The UB1, UB5, UB6, and
Si3000 register configuration vary with the customer’s production hardware. The UB5 register serves as the
general volume control in this mode.
AT:U72,075E OK
Configure Si3000 Register 7:
0 dB RX PGA gain
Enable SPKRL
Mute SPKRR
AT:U72,0900 OK
Configure Si3000 Register 9:
0 dB Line Out attenuation
0 dB Speaker output attenuation
AT:U0B1,0 OK
Disable Si3000-to-DAA transmit gain
path. This ensures codec tones are not
sent to the FDV and DTMF.
AT:U0B5,0 OK
Disable DAA-to-Si3000 receive gain
path. This ensures line events such as
CID and ring tone are not heard via the
codec.
AT:U199&FFF7 OK
Enable speaker for local ring tone/alert
tones.
Table 119. Initialization Sequence (Continued)