Call blocking to
prevent unauthorized use of phones is implemented by matching dialed numbers
against a pattern of specified digits and matching the time against the time of
day and day of week or date that has been specified for Call Blocking. You can
specify up to 32 patterns of digits for blocking.
When a user attempts
to place a call to digits that match a pattern that has been specified for Call
Blocking during a time period that has been defined for Call Blocking, a fast
busy signal is played for approximately 10 seconds. The call is then terminated
and the line is placed back in on-hook status.
Cisco Unified CME session application accesses the current after-hours
configuration and applies it to calls originated by phones that are registered
to the Cisco Unified CME router. Call blocking applies to all IP phones in
Cisco Unified CME, although individual IP phones can be exempted from all call
In Cisco CME 3.4 and
later versions, the same time-based call-blocking mechanism that is provided
for SCCP phone and on analog phones connected to SCCP-controlled analog
telephone adaptors (Cisco ATA) or SCCP-controlled foreign exchange station
(FXS) ports is expanded to SIP endpoints.
In Cisco CME 3.4 and
later, call-blocking configuration applies to all SCCP, H.323, SIP and POTS
calls that go through the Cisco Unified CME router. All incoming calls to the
router, except calls from an exempt phone, are also checked against the
Prior to Cisco
Unified CME 4.2(1), all Call Blocking features are implemented globally and
uniformly on each phone in the system. All phones are similarly restricted
according to time, date, location, and other call blocking characteristics.
Call Blocking is not supported on ephone-dns that are configured to use the
trunk feature, and Call Blocking did not apply to second-stage trunk dialing.
In Cisco Unified CME
4.2(1) and later versions, you have the flexibility to set different call block
calendars and call block patterns to phones in different departments, to block
certain trunk dialing as required, and to configure Call Blocking on a
particular SCCP IP phone by creating and applying a template to that phone.
Configure Call Blocking.