When you configure a shared extension in Cisco Configuration Professional, which two
characteristics should be the same on both phones, so that the phones can successfully use a
shared extension? (Choose two.)

A.
monitor mode

B.
MAC address

C.
ephone-dn

D.
number

E.
user ID

Explanation:
You can set up one or more lines with a shared-line appearance. A Cisco CallManager system
considers a directory number to be a shared line if it appears on more than one device in the same
partition. For example, if directory number 9600 on phone A is in the partition called Dallas and on
phone B in the partition called Texas, that directory number does not represent a shared-line
appearance. (Ensure the directory number 9600 for phone A and phone B are in the same
partition; for example, Dallas.)
In a shared-line appearance, for example, you can set up a shared line, so a directory number
appears on line 1 of a manager phone and also on line 2 of an assistant phone. Another example
of a shared line involves a single incoming 800 number that is set up to appear as line 2 on every
sales representative phone in an office.

You can also choose to update a directory number and have the updates apply to all devices that
share the directory number.
The following information provides tips about and lists the restrictions for using shared-line
appearances with Cisco CallManager.
Shared Line Tips
Use the following tips when configuring shared lines:
• You create a shared-line appearance by assigning the same directory number and route partition
to different devices.
• If multiple devices share a line, each device name displays in the Associated Devices pane of
the directory number in the Directory Number Configuration window in Cisco CallManager
Administration.
• If you change the Calling Search Space or Call Forward and Pickup settings on any device that
uses the shared line, the changes apply to all devices that use that shared line.
• To stop sharing a line appearance on a device, change the directory number or partition name
for the line and update the directory number in the Directory Number Configuration window in
Cisco CallManager
Administration.
• In the case of a shared-line appearance, Remove From Device removes the directory number on
the current device only and does not affect other devices.
• Most devices with a shared-line appearance can make or receive new calls or resume held calls
at the same time.
Incoming calls display on all devices that share a line, and anyone can answer the call. Only one
call remains active at a time on a device.
Link:
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/5_0_1/ccmsys/a03dn.html