Guest

Cisco BTS 10200 Softswitch

Emergency Callback

Table Of Contents

Emergency Callback Feature Module

Understanding the Emergency Callback Feature

Feature Interactions

Call Waiting

Other Terminating Features

Provisioning


Emergency Callback Feature Module


Revised: July 29, 2008

This document describes the Emergency Callback feature for Release 6.0 of the Cisco BTS 10200 Softswitch and explains how to use it.

Understanding the Emergency Callback Feature

The Emergency Callback (ECB) feature allows public safety answering point (PSAP) numbers to call back a subscriber provisioned on the Cisco BTS 10200 Softswitch. The BTS 10200 treats these callbacks as special high-priority calls so that for the subscriber with an active PSAP call, all terminating features are disabled except Call Waiting (CW) and Call Forwarding Busy (CFB). The advantage of the ECB feature is that the BTS 10200 blocks all terminating services that could potentially interrupt a call from a PSAP line.

ECB is an office-based feature. The BTS 10200 provides ECB to any subscriber associated with an office service that has ECB.

ECB is available when you assign it to the office service ID, then add the PSAP line directory number (DN) to the emergency_number_list table per the instructions for the Emergency Number List table in the Cisco BTS 10200 CLI Database. The BTS 10200 then determines which incoming calls should be classified as ECB. The BTS 10200 first checks the list of DNs specified in the emergency number list to determine if the calling DN is a PSAP number. If the DN is in the list, the BTS 10200 treats the call as ECB, blocking all terminating services except CW and CFB.

For additional information about the interaction between ECB and the CW and CFB features, refer to Feature Interactions.

Feature Interactions

This section describes the interactions between ECB and terminating features.

Call Waiting

A subscriber who is in an ECB call cannot invoke CW. The following table describes the interaction between ECB and CW.

If
Then

The ECB subscriber has an active call and receives a call from a PSAP line.

The terminating subscriber can accept the incoming ECB call but will be unable to toggle back to the first caller because all hookflashes are blocked.

The subscriber is in a call with two other callers using CW and receives a call from a PSAP line.

The PSAP caller hears a busy tone because no more calls can be accommodated in CW.

The subscriber is in a call with a PSAP line and receives a call from a normal subscriber.

The second caller hears the busy tone but the ECB subscriber does not hear the CW tone. If the ECB subscriber subscribes to Call Forwarding Busy (CFB), the second call is forwarded to the new DN.

The subscriber has an active PSAP call and receives a call from another PSAP line.

The second PSAP caller hears a busy tone but the subscriber does not hear a CW tone.


Other Terminating Features

The following table describes the interaction between ECB and other features.

Feature
Behavior with ECB

Anonymous Call Rejection

A PSAP call is always accepted by the ECB subscriber even if the caller is anonymous. If the calling party is unidentifiable to the BTS 10200, the call is not classified as ECB. If ACR is activated, the call is rejected.

Automatic Recall

The ECB subscriber cannot invoke the automatic recall feature for a PSAP line.

Busy Line Verification

If the ECB subscriber is already engaged in an ECB call, the subscriber does not receive an interrupt and the PST is played back.

CALEA

Communications Assistance for Law Enforcement Act (CALEA) is supported for ECB exactly as it is with normal calls.

Call Forwarding Busy

If the ECB subscriber is in a call, the PSAP caller hears a busy tone but the call is not forwarded.

Call Forwarding No Answer

If the subscriber does not pick up the call, it is not forwarded to the forwarding DN. The CFNA timer is not started and the phone continues to ring.

Call Forwarding Unconditional

The subscriber receives the PSAP call even if CFU is activated.

Call Hold/Call Park/Call Transfer/Three Way

These services are inhibited during a PSAP call.

Calling Number Delivery/Calling Name Delivery

The PSAP calling name and number are not displayed to the subscriber.

Call Waiting

Refer to Call Waiting for a description of ECB interaction with CW.

Do Not Disturb

The subscriber receives PSAP calls even if DND is activated.

Directed Call Pickup

No other subscribers can pick up PSAP calls.

Distinctive Ringing

Distinctive ringing is not available.

Multi-Line Hunt Group

There is no special handling for MLHG. MLHG behaves the same for ECB and non-ECB calls.

Seasonal Suspend

A subscriber who has the seasonal suspend feature enabled can receive calls.

Selective Call Acceptance

The PSAP call is not checked against the SCA list, so the call is not blocked.

Selective Call Rejection

The PSAP call is not checked against the SCR list, so the call is not blocked.

Temporary Disconnect

Temporary disconnect subscribers do not receive ECB calls.


Provisioning

Use the following procedure to provision the Emergency Callback feature.


Step 1 Add ECB to the feature table.

add feature fname=ECB; tdp1=TERMINATION_ATTEMPT_AUTHORIZED; tid1=ECB_TRIGGER; ttype1=R; 
description=Emergency Callback; feature_server_id=FSPTC235;

Step 2 Add ECB to the list of features available to the subscriber as part of the office-based services. ECB is available to all subscribers associated with the service ID.

add service id=499;fname9=ECB

Step 3 Provision the PSAP emergency list by specifying the PSAP line DN.

add emergency_number_list digit_string=2145551212