SmartACFL



V.90/K56flex Modem Device Sets with SmartDAA Technology for Low Power Applications

6

Conexant

Doc. No. 100444A

Proprietary Information

Voice/Speakerphone Mode (S Models)

S models include additional telephone handset,

external microphone, and external speaker

interfaces that support voice and full-duplex

speakerphone operation.

Hands-free full-duplex telephone operation is

supported in Speakerphone Mode under host

control. Speakerphone Mode features an advanced

proprietary speakerphone algorithm which supports

full-duplex voice conversation with acoustic, line, and

handset echo cancellation. Parameters are

constantly adjusted to maintain stability with

automatic fallback from full-duplex to pseudo-duplex

operation. The speakerphone algorithm allows

position independent placement of microphone and

speaker. The host can separately control volume,

muting, and AGC in microphone and speaker

channels.

V.70 DSVD Mode using RCDSVD SCP Device

(S Models)

On-board DSVD operation requires installation of the

optional RCDSVD SCP (R6715-14). GSM operation

is not available when the RCDSVD SCP is

connected because MCU port PB5 is used for SCP

chip select output (~SVDSEL) rather than address

line A18 output which is needed to support the 4M

ROM.

DSVD provides full-duplex digital simultaneous voice

and data over a single telephone line. DSVD uses

codecs in the RCDSVD SCP to code (compress)

analog speech signals on the RCDSVD LINEIN pin

or MICIN pin for passing to the modem controller in

digitized form. DSVD also decodes (decompresses)

coded speech received from the modem controller

for routing to the RCDSVD LINEOUT pin or

SPKP/SPKN pins in analog form.

DSVD operates in accordance with ITU-T

interoperable G.729 and G.729 Annex A with

interoperable G.729 Annex B. Voice activity

detection supports speech coding at an average bit

rate significantly lower than 8.0 kbps.

DSVD decoder timing recovery algorithm

compensates for clock skew, asynchronous host-to-

decoder data transfer delay, intervening variable

length data block transmission delay, and loss of

encoded speech data.

The voice interface can be in the form of a headset,

handset or a microphone and speaker (half-duplex

speakerphone). Handset echo cancellation supports

handset use through a hybrid.

In Handset Mode, the RCDSVD SCP interfaces to

the telephone interface circuit using the Line Input

(LINEIN) and Line Out (LINEOUT) lines. In Headset

or Speakerphone Mode, the RCDSVD SCP

interfaces to the audio interface circuit using the

Microphone Input (MICIN) and Speaker out (SPKR)

lines.

GSM (Parallel Host or PC Card Interface)

GSM operation requires installation of 4M (512k x 8)

ROM (56 models) or 2M ROM (33 and 14 models).

ON-board DSVD is not available when the 4 Mbit

ROM is installed since the MCU port PB5 is used for

address line 18 rather than RCDSVD SCP chip

select output (~SVOSEL).

Features supported in GSM operation include:

• Data modem

− V.21, V.23, V.22, V.22 bis, V.32

− ISDN interoperability: 300 bps to 9600 bps

• Transparent asynchronous mode up to 9600 bps

• Non-transparent mode (RLP) up to 9600 bps

• Fax modem send and receive rate up to 9600 bps

• AT GSM commands (ETSI 07.07)

• GSM direct connect

• Firmware interface for OEM-provided phone driver

• Automatic GSM cable presence detection

• Built-in parallel host (16550A UART) interface

Sleep Mode

Sleep mode is supported in the modem device set

and the RCDSVD SCP device.

Additional Information

Additional information is described in the SmartACFL

Modem Device Family with SmartDAA Technology

for Low Power Applications Designer’s Guide (Doc.

No. 100446) and the Command Reference Manual

(Doc. No. 100500).