2.11.11 One-numbered ExtensionDescriptionIt is possible to share one extension number between a main extension and a sub extension as a pairedextension. The sub extension that is paired with the main extension can be called simultaneously by theextension number of the main extension (paired main extension number). When an incoming call is receivedat the main extension, it is treated as a call for the paired main extension number and the incoming call willarrive at the sub extension simultaneously.A user can pick up the call for the paired extension by entering the corresponding feature number or pressingthe corresponding flexible button. However, if one of the extensions is in a conference call, the other extensioncannot pick up the call.Conditions• The following extensions can be assigned as a main/sub extension.PT, SLT, IP-PT (except S-PS), SIP extension (including KX-UT series SIP phones and general SIP phones)• If an S-PS is paired as the sub extension, operation is the same as Wireless XDP.• The paired main extension number is displayed on the sub extension when the telephone is idle. However,for KX-UT series SIP phones and general SIP phones, the original extension number is displayed on thesub extension when the telephone is idle.• If a main extension is already configured with Wireless XDP or paired with one-numbered extension, themain extension cannot be paired with another sub extension.• The sub extension operates according to the COS and extension settings of the main extension (exceptkey settings, incoming line preference, and outgoing line preference).• When calling from a sub extension, the caller information (extension number, extension Name, CLIP/CNIP)of the paired main extension number is used.• When an incoming call is received at a one-numbered extension, the behaviour differs depending on thetype of telephone, as follows:[KX-NT series/DPT]• If the main extension is busy and there is a flexible button available to receive the call, the call waitingfeature can function.• If the main extension cannot receive the incoming call, the call waiting feature will not function.[SLT]• If the main extension is an SLT and is busy, the sub extension cannot receive the call.[KX-UT series]• If the main extension is a KX-UT series SIP phone and the sub extension is an SLT or a KX-UT seriesSIP phone, the sub extension cannot receive calls while the main extension is busy.• If the main extension is a KX-UT series SIP phone, neither the main extension nor the sub extensioncan receive calls. This condition applies regardless of the type of telephone used for the sub extension.[KX-UT series SIP phone and general SIP phones.]• The no-ring or delayed ringing features are not activated when a new call is received at a pairedextension during a call. In this case, the telephone will ring normally.• When making an extension call to a paired main extension number using voice-calling, a ring tone is heardat the sub extension.• When a call is received to a paired main extension number in LCS with Hands-free mode, the call will notbe received at a sub extension.• The following features are available only at the main extension.– OHCA (® 2.10.4.3 Off-hook Call Announcement (OHCA))– Whisper OHCA (® 2.10.4.4 Whisper OHCA)• When a paired main extension number is paged, the sub extension will not be paged. (® 2.17.1 Paging)• When a paired main extension number is called for a conference, the call will also arrive at the subextension.184 Feature Guide2.11.11 One-numbered Extension
