https://www.cisco.com/en/US/product...s_tech_note09186a00801f3b4e.shtml#topic1 Multiple Calls Per Line
These are the Multiple Calls Per Line enhancements in Cisco CallManager 4.x:
Overcomes the limitation on the maximum number of calls per line.
Introduces the CFB Trigger concept to replace the original Call Waiting flag.
Configurable CFNA timer per line.
Maximum Number of Calls
In Cisco CallManager 3.x , the maximum number of calls allowed per DN is restricted to two. The new feature in Cisco CallManager 4.x makes this count database configurable, per line appearance, per cluster. However, due to the limited memory available in devices such as Cisco 7914 IP phones and the large number of lines that can be attached to them, it is necessary to limit the maximum number of calls for all lines on one single device. This limitation is stored in the database per device type.
For Multiple Call Display (MCD) devices, the default maximum number of calls is set to 4 per line appearance.
For non-MCD devices, this number remains at 2, due to the limited display capability. The default is set to 2 as well.
The sum of the maximum number of calls for all line appearances per device should not exceed the limit for that device type. If it exceeds the limit, the device is no longer able to register.
Once this limit is reached, a user cannot use that line to initiate new calls and no new incoming calls are offered.
Note: An MCD device can display more than two call instances per DN at any given time. The display information for one call instance does not interrupt the display information for another call instance. Cisco IP Phones 7960 and 7940 are MCD capable, while 7910, SP12, and 30VIP are not.
This is a REAL issue if you are used to having capabilites of taking more than a one or two calls.
