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Operational Features
5-14 41-001343-02 REV04 – 05.2014
Configurable Emergency Call Behavior
Administrators have the option of changing the default behavior of the IP phones when an emergency call (i.e. a call
made to an emergency number matching one of the values defined in the “emergency dial plan” parameter) is placed.
If the “emergency call connection hold enabled“ configuration parameter is enabled, the IP phones employ the follow-
ing behaviors:
• Connection Hold: If an emergency call is placed, the IP phones ensure the voice/audio path and other resources asso-
ciated with the emergency call are continually active, even if the caller hangs up the phone (i.e. the handset is placed
on-hook).
– If the handset is placed on-hook, the phone automatically switches to speakerphone mode ensuring that the call is
still active. Alternatively, if the handset is taken off-hook, the phone automatically switches to handset mode.
– All softkey and hardkey events (e.g. hold, conference, transfer, end call, park, mute, etc...) are disabled as they may
impede or be disruptive to the active call.
– The phone does not allow for the origination or termination of any call while the phone is connected to the emer-
gency services agent. All incoming calls and pages are ignored and a busy tone is presented to the remote caller.
• Enhanced Called Party Hold: As a complement to the Connection Hold feature, Enhanced Called Party Hold allows
the voice/audio path to be established the moment the emergency call is placed.
– When a caller places a call to an emergency services number, all Connection Hold features are activated, even if the
SIP session has not been established completely.
– Even if the caller abandons the call before the emergency services agent answers, the voice/audio path and Con-
nection Hold features will still be active.
• Forced Disconnect: As the Connection Hold feature ensures that the caller cannot terminate the call, the only way
the call can be terminated is if the emergency services agent forces the disconnection by ending the call himself/her-
self.
The “emergency call connection hold enabled“ parameter is disabled by default.
Configuring Emergency Call Behavior
Use the following procedures to configure the IP phone’s behavior when emergency calls are placed.
User Dial Plan Setting
The IP Phones have a parameter for configuring a dial plan that distinguishes between calling a real PSTN number and a
number that looks like a PSTN number but is actually on an IP network.
This parameter is “sip user parameter dial plan”. Using the configuration files, an Administrator can configure a dial plan
corresponding to a IP network number (i.e. 6xx|8xxxx|9xxxxxxx) that the phone checks before sending the SIP packet.
If for example, the number that was dialed was 645, the phone checks the dial plan and matches the number to the dial
plan (6xx in the example above), before sending out the SIP packet. The SIP packet header omits the user parameter
user=ip (i.e. “To: <sip:645@10.30.102.24:10060>“) identifying the number as one from an IP network. If the number that
was dialed was 456-2345, the phone tries to match the number to the dial plan before sending out the SIP packet but as
it is not part of the dial plan the phone identifies the number as a PSTN number. The SIP packet header in this case indi-
cates user=phone (i.e., “To: <sip:4562345:10060;user=phone>“).
Configuration Files
For specific parameters you can set in the configuration files, see Appendix A, the section, “Emergency Call Behavior Settings” on pageA-15.
Note:
• Entering a dial plan value for this parameter enables this feature. Entering no value for this parameter in the config-
uration files, disables this feature.
• You can configure the “sip user parameter dial plan” parameter on a global basis only. If it is misconfigured, then
the parameter is ignored.