Linksys SPA 900 manual Field Description

Chapter 5 Linksys IP Phone Field Reference

Ext Tab

call actually uses G.729a. If the G.729a resource is already allocated and since only one G.729a resource is allowed per device, no other low-bit-rate codec may be allocated for subsequent calls; the only choices are G711a and G711u. On the other hand, two G.723.1/G.726 resources are available per device.

Therefore it is important to disable the use of G.729a in order to guarantee the support of two simultaneous uses of the G.723/G.726 codecs.

Field		Description
Preferred Codec		Preferred codec for all calls. (The actual codec used in a call still depends on the outcome of
		the codec negotiation protocol.) Select one of the following: G711u, G711a, G726-16,
		G726-24, G726-32, G726-40, G729a, or G723.
		Defaults to G711u.
Silence Supp Enable		To enable silence suppression so that silent audio frames are not transmitted, select yes. Oth-
		erwise, select no.
		Defaults to no.
Use Pref Codec Only		To use only the preferred codec for all calls, select yes. (The call fails if the far end does not
		support this codec.) Otherwise, select no.
		Defaults to no.
Echo Canc Enable		Enable the use of the echo canceller.
		Defaults to yes.
Echo Canc Adapt Enable		Enable the echo canceller to adapt.
		Defaults to yes.
Echo Supp Enable		Enable the use of echo suppressor. If <Echo Canc Enable> is “no,” this parameter is
		ignored.
		Defaults to yes.
G729a Enable		To enable the use of the G.729a codec at 8 kbps, select yes. Otherwise, select no.
		Defaults to yes.
G723 Enable		To enable the use of the G.723a codec at 6.3 kbps, select yes. Otherwise, select no.
		Defaults to yes.
G726-16 Enable		To enable the use of the G.726 codec at 16 kbps, select yes. Otherwise, select no.
		Defaults to yes.
G726-24 Enable		To enable the use of the G.726 codec at 24 kbps, select yes. Otherwise, select no.
		Defaults to yes.
G726-32 Enable		To enable the use of the G.726 codec at 32 kbps, select yes. Otherwise, select no.
		Defaults to yes.
G726-40 Enable		To enable the use of the G.726 codec at 40 kbps, select yes. Otherwise, select no.
		Defaults to yes.
FAX CED Detect Enable		To enable detection of the fax Caller-Entered Digits (CED) tone, select yes. Otherwise,
		select no.
		Defaults to yes.
	Linksys IP Phone Administrator Guide
5-44		Firmware Version 5.1