1.10 Conversation Features88 Feature GuideInstallation Manual ReferencesInstallation Manual2.6.2 Parallel Connection of the Extensions1.10.9 Calling Party Control (CPC) Signal DetectionDescriptionThe Calling Party Control (CPC) signal is an on-hook indication (disconnect signal) sent froma CO line when the other party hangs up. To maintain efficient utilization of CO lines, the PBXmonitors each line’s status and when CPC signal is detected on a line, the PBX disconnectsthe line and alerts the extension with a reorder tone.Conditions• CPC signal detection is programmable for incoming CO line calls ( LCOT CPC SignalDetection Time—Incoming [414]), and for outgoing CO line calls ( LCOT CPC SignalDetection Time—Outgoing [413]).• If your telephone company sends signals similar to CPC, it is recommended not to enableCPC signal detection on outgoing CO line calls.• If CPC signal is detected during a conference call ( 1.13.1.2 Conference), the line isdisconnected. The remaining parties stay connected.• If CPC signal is detected during a call between a caller using the Direct Inward SystemAccess (DISA) feature ( 1.15.6 Direct Inward System Access (DISA)) and an extensionor an outside party, the line is disconnected.