PRIVATE BRANCH CODELESS TELEPHONE CONNECTION SYSTEM

PROBLEM TO BE SOLVED: To make it possible to use even a cordless telephone set brought from another office downloading an extension number in the cordless telephone set brought form outside from a base station where the extension numbers of plural cordless telephone sets to be used in a base station device private branch are registered. SOLUTION: If an extension number or an abbreviated dial of an accomodated terminal 3, is registered in the base station device 4 it is possible to use a cordless telephone set 14 by an easy operation with these pieces of information downloaded in the cordless telephone set 14 from the base station device 4 even when another office or the like is visited. If there is an unregistered cordless telephone set 14 in a private branch, the extension number registered in the base station device 4 is downloaded by using a radio interface of the cordless telephone set 14. The cordless telephone set 14 which is unregistered by download processing has the extension number of the cordless telephone set 14 used in this private branch registered.