Cisco Systems ATA 186 Debugging FAX Pass-through Mode, Log event, timestamp1, timestamp2 , pt pt

Chapter 6 Configuring and Debugging Fax Services

Debugging the Cisco ATA 186/188 Fax Services

Table 6-2 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 Cisco ATA
	transmitted G.723.1-encoded voice packets.
[ch] DPKT 1st:	The first voice packet that the Cisco ATA received was of RTP payload
<timestamp1>	type pt for the channel ch with timestamp of timestamp1, and the local
<timestamp2>, pt <pt>	decoding timestamp was set to timestamp2.
	For example, [0]DPKT 1st: 1491513359 1491512639, pt 4 indicates
	that the first RTP packet that the Cisco ATA 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>	Channel ch received an NSE packet of event with payload type of
NSE pkt <event>	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	Channel ch transmitted an NSE packet of event with payload type of
pkt <event>	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.

Debugging FAX Pass-through Mode

When the Cisco ATA 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 Cisco ATA 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.

Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator’s Guide for MGCP (version 3.0)

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