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Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide (H.323)
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Chapter7 Configuring and Debugging Fax Services
Using FAX Mode
Using FAX Mode
Use fax mode when the gateways in the network do not support fax pass-through mode or dial-peer
configuration.
You can set one or both lines of the Cisco ATA to G.711-only fax mode. This mode allows the fax
machine connected to the CiscoATA to communicate directly with the far endpoint with no fax signaling
event occurring between the two gateways.
This section contains the following topics:
•Configuring the Cisco ATA for Fax Mode, page 7-6
•Configuring the Cisco ATA for Fax Mode on a Per-Call Basis, page 7-7
•Configuring the Cisco IOS Gateway for Fax Mode, page 7-7

Configuring the Cisco ATA for Fax Mode

G.711-only fax mode operation requires configuration of one parameter—AudioMode.
Description
The AudioMode parameter is a 32-bit value. The lower 16 bits apply to the Phone 1 port of the
Cisco ATA, and the upper 16 bits to the Phone 2 port. The following is an example of the Phone 1 port
of the Cisco ATA configured for G.711-only fax mode:
Example
0xXXXX0012
Translation
This setting translates to the bitmap:
xxxx xxxx xxxx xxxx 0000 0000 0001 0010
•Bit 0 = 0—Disables G.711 silence suppression (VAD).
•Bit 1 = 1—Uses G.711 only, does not user the low bit-rate codec.
•Bit 2 = 0—Disables Fax CED tone detection.
•Bit 4 = 1, Bit 5 = 0—DTMF transmission method: out-of-band through negotiation
•Bit 6 = Bit 7 = 0—Hookflash transmission method: disables sending out h ookflash
Note The values XXXX in the example do not apply to the Phone 1 port of the Cisco ATA.
To configure the same value for the Phone 2 port of the CiscoATA, the value would be 0x0012XXXX. The
configuration of one port is independent from the configuration of the other port.
Note The AudioMode configuration overrides the values of the following three parameters: RxCodec,
TxCodec, and LBRCodec. For example, if these three parameters are each set to 0 (for G.723), the
Cisco ATA would still use G.711 if AudioMode is set to 0x00120012. With this configuration, the
Cisco ATA sends both G.711µ-law and G.711A-law as preferred codecs to a peer voice gateway.