Cisco Systems ATA 188 Debugging FAX Pass-through Mode

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Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide (H.323)

OL-4008-01

Chapter7 Configuring and Debugging Fax Services

Debugging the Cisco ATA 186/188 Fax Services

Debugging FAX Pass-through Mode

When the CiscoATA is configured to use fax pass-through mode, the fax call session can be established

with an arbitrary voice codec. Once the voice call has been established, fax machines can signal their

presence by means of a CED tone or V.21 preamble flag, after which the gateways send NSE packets to

initiate switchover.

Note For fax pass-through mode, check the Cisco ATA debug log to verify that it is acting as an originating

gateway as well as a terminating gateway.

Terminating-Gateway Example

When the CiscoATA is used as a terminating gateway for a fax session, make sure the following

conditions are true:

•The Cisco ATA transmits CED-tone-event NSE packets.

•The encoder switchover to G.711 occurs during the NSE-packet transaction.

Table7-2 Debug Log Examples

Log event Description

[ch] Enable encoder <pt> Voice encoder type pt is enabled for the channel ch, where pt can be 0

for G.711µ-law, 4 for G.723.1, 8 for G.711A-law, and 18 for G.729.

For example, [0]Enable encoder 4 indicates that the CiscoATA

transmitted G.723.1-encoded voice packets.

[ch] DPKT 1st:

The first voice packet that the Cisco ATA received was of RTP payload

type pt for the channel ch with timestamp of timestamp1, and the local

decoding timestamp was set to timestamp2.

For example, [0]DPKT 1st: 1491513359 1491512639, pt 4 indicates

that the first RTP packet that the CiscoATA received was

G.723.1-encoded for channel 0.

[ch] codec: <pt1> => <pt2> Voice codec switchover occurred. The voice encoder type switched from

pt1 to pt2 for the channel ch.

For example, [0]codec: 4 => 0 indicates that the local voice encoder

on the Cisco ATA switched from G.723.1 to G.711µ-law.

[ch] Rx MPT PT=<NSEpt>

NSE pkt <event>

Channel ch received an NSE packet of event with payload type of NSEpt.

For event, c0XXXXXX indicates a CED tone event, and c1XXXXXX

indicates a phase reversal event.

For example, [0]Rx MPT PT=100 NSE pkt c0000000 indicates that the

Cisco ATA received a CED tone event NSE packet with payload type of

100.

[ch] Tx MPT PT=<pt> NSE

pkt <event>

Channel ch transmitted an NSE packet of event with payload type of

NSEpt. For event, c0XXXXXX indicates a CED tone event, and

c1XXXXXX indicates a phase reversal event.

For example, [0]Tx MPT PT=100 NSE pkt c0000000 indicates that the

ATA transmitted a CED tone event NSE packet with payload type of

100.