On the DN webpage click help->help for this Page, you will get the following explanation for thos two fields:
Maximum Number of Calls
You can configure up to 200 calls for a line on a device, with the limiting factor being the total number of calls that are configured on the device. As you configure the number of calls for one line, the calls that are available for another line decrease.
The default specifies 4. If the phone does not allow multiple calls for each line, the default specifies 2.
For CTI route points, you can configure up to 10,000 calls for each port. The default specifies 5000 calls. Use this field in conjunction with the Busy Trigger field.
Note : Although the default specifies 5000 calls for maximum number of active calls that can be configured on a CTI route point, Cisco recommends that you set the maximum number of calls to no more than 200 per route point. This will prevent system performance degradation. If the CTI application needs more than 200 calls, Cisco recommends that you configure multiple CTI route points.
Tip : To review how this setting works for devices with shared line appearances, refer to Shared Line Appearance in the Cisco CallManager System Guide.
Busy Trigger
This setting, which works in conjunction with Maximum Number of Calls and Call Forward Busy, determines the maximum number of calls to be presented at the line. If maximum number of calls is set for 50 and the busy trigger is set to 40, then incoming call 41 gets rejected with a busy cause (and will get forwarded if Call Forward Busy is set). If this line is shared, all the lines must be busy before incoming calls get rejected.
Use this field in conjunction with Maximum Number of Calls for CTI route points. The default specifies 4500 calls.
Tip : To review how this setting works for devices with shared line appearances, refer to Shared Line Appearance in the Cisco CallManager System Guide.
