Linksys SPA921 Cisco Small Business IP Phone SPA9X1 Administration Guide - Page 150

Choose None, NSE, or ReINVITE., AVT: use RFC2833 AVT event=16

Page 150 highlights

Chapter 5 Linksys IP Phone Field Reference Ext Tab Field FAX CNG Detect Enable FAX Passthru Codec FAX Codec Symmetric FAX Passthru Method FAX Process NSE FAX Disable ECAN DTMF Tx Method Hook Flash Tx Method Symmetric RTP Release Unused Codec Description Defaults to yes. Codec to use for FAX passthru (G711u or G711a). Defaults to G711u. Force unit to use symmetric codec druing FAX passthru. Defaults to yes. Choose None, NSE, or ReINVITE. Defaults to NSE. Defaults to yes. Set to yes to automatically disable Echo Canceller when FAX tone is detected. Defaults to no. Select the method to transmit DTMF signals to the far end: InBand, AVT, INFO, Auto, InBand+INFO, or AVT+INFO. InBand sends DTMF using the audio path. AVT sends DTMF as AVT events. INFO uses the SIP INFO method. Auto uses InBand or AVT based on the outcome of codec negotiation. Defaults to Auto. Select the method to signal Hook Flash events: • None: do not signal hook flash events • AVT: use RFC2833 AVT (event=16) • INFO: use SIP INFO method with the signal line "signal = hf" in the message body. The MIME type for this message body is taken from the parameter. Defaults to None. Enable symmetric RTP operation. If enabled, the SPA sends RTP packets to the source address of the last received valid inbound RTP packet. If disabled, the SPA sends RTP to the destination as indicated in the inbound SDP. Defaults to yes. This feature allows the release of codecs not used after codec negotiation on the first call, so that other codecs can be used for the second line. To use this feature, select yes. Otherwise, select no. Defaults to yes. A codec resource is considered allocated if it has been included in the SDP codec list of an active call, even though it eventually might not be chosen for the connection. If the G.729a codec is enabled and included in the codec list, that resource is tied up until the end of the call whether or not the call actually uses G.729a. If the G729a resource is already allocated (and since only one G.729a resource is allowed per SPA), no other low-bit-rate codec can be allocated for subsequent calls. The only choices are G711a and G711u. Since two G.723.1/G.726 resources are available per SPA, you should disable the use of G.729a to guarantee support for two simultaneous G.723/G.726 codecs. Firmware Version 5.1 Linksys IP Phone Administrator Guide 5-45

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Linksys IP Phone Administrator Guide
Firmware Version 5.1
Chapter 5
Linksys IP Phone Field Reference
Ext Tab
A codec resource is considered allocated if it has been included in the SDP codec list of an active call,
even though it eventually might not be chosen for the connection. If the G.729a codec is enabled and
included in the codec list, that resource is tied up until the end of the call whether or not the call actually
uses G.729a. If the G729a resource is already allocated (and since only one G.729a resource is allowed
per SPA), no other low-bit-rate codec can be allocated for subsequent calls. The only choices are G711a
and G711u.
Since two G.723.1/G.726 resources are available per SPA, you should disable the use of G.729a to
guarantee support for two simultaneous G.723/G.726 codecs.
FAX CNG Detect Enable
Defaults to yes.
FAX Passthru Codec
Codec to use for FAX passthru (G711u or G711a).
Defaults to G711u.
FAX Codec Symmetric
Force unit to use symmetric codec druing FAX passthru.
Defaults to yes.
FAX Passthru Method
Choose None, NSE, or ReINVITE.
Defaults to NSE.
FAX Process NSE
Defaults to yes.
FAX Disable ECAN
Set to yes to automatically disable Echo Canceller when FAX tone is detected.
Defaults to no.
DTMF Tx Method
Select the method to transmit DTMF signals to the far end: InBand, AVT, INFO, Auto,
InBand+INFO, or AVT+INFO. InBand sends DTMF using the audio path. AVT sends
DTMF as AVT events. INFO uses the SIP INFO method. Auto uses InBand or AVT based
on the outcome of codec negotiation.
Defaults to Auto.
Hook Flash Tx Method
Select the method to signal Hook Flash events:
None: do not signal hook flash events
AVT: use RFC2833 AVT (event=16)
INFO: use SIP INFO method with the signal line “signal = hf” in the message body. The
MIME type for this message body is taken from the <Hook Flash MIME Type> parame-
ter.
Defaults to None.
Symmetric RTP
Enable symmetric RTP operation. If enabled, the SPA sends RTP packets to the source
address of the last received valid inbound RTP packet. If disabled, the SPA sends RTP to
the destination as indicated in the inbound SDP.
Defaults to yes.
Release Unused Codec
This feature allows the release of codecs not used after codec negotiation on the first call,
so that other codecs can be used for the second line. To use this feature, select yes.
Otherwise, select no.
Defaults to yes.
Field
Description