# Uniform Call Distribution - Call Overflow

Call Overflow refers to the automatic rerouting of calls which have not been answered within a programmable length of time. Two levels of rerouting are available and are based on the originating device (classified by trunk type or internal station) and the condition of called station or hunt group (Busy/Do Not Disturb or No Answer).

Through system rerouting, all calls that overflow from a voice group and encounter a busy alternate destination will reroute automatically (queue) onto the next alternate destination. If the overflow destination is another voice group with first and second level RAD messages, only the second level RAD message of the overflow group will be heard by the caller.

NOTE: A station can also be programmed to Always Reroute based on the current system status (Day, Night 1, Night 2).

- The Call Forward No Answer (CFNA) Timer and the Answer Plus System Rerouting Timer control call rerouting for no answer conditions and for rerouting of calls to busy hunt groups.

- The Uniform Call Distribution (UCD) feature uses the Class of Service of the first member of the hunt group to determine the values of the CFNA and system rerouting timers for all members in the group.

- The Attendant Overflow feature uses the Class of Service for the first console assigned in system programming to determine the CFNA and Answer Plus System Rerouting timer values for all consoles in the group.

- The CFNA timer determines how long the system rings a hunt group or answering point, or leaves a caller in the queue before overflowing to the Call Rerouting First Alternative Answer point.

- The CFNA timer starts counting when the call routes to the hunt group or answering point and runs independently of the RAD timers. To prevent rerouting while the caller is listening to an announcement, ensure that the CFNA timer expires during a period of music rather than during an announcement.

- Uniform Call Distribution uses the Answer Plus System Rerouting Timer in the Class of Service Options form (rather than the Call Rerouting timer on the System Options form).

- The Answer Plus System Rerouting timer starts counting at the same time as the CFNA timer. When it reaches its programmed value, the call is rerouted from the first alternate to the second alternate point. By giving the Answer Plus System Rerouting timer a higher value than the CFNA timer, two levels of rerouting are ensured.