PURPOSE: To prevent an MW display from being released against the will of the operator, by operating the MW display release only from a button telephone set relating to a message waiting MW display.
CONSTITUTION: The operation for the message waiting MW display is performed at a button telephone set 21 and the MW display is attained with a button telephone set 2m. Even when the telephone set 2m hooks off and makes communication with other telephone set, the MW display remains lighted. When the telephone set 2m hooks off and an extension button and an MW button are depressed, then a main control circuit 9 receives this information, recognizes that the release of the MW display is indicated and the extinguishment of the MW display is commanded to the telephone set 2m. Thus, the MW display of the telephone set 2m is turned off.
| JPS61256893 | TELEPHONE SET |
| JPH0335686 | TRUNK RESPONDING SYSTEM FOR PRIVATE AUTOMATIC BRANCH EXCHANGE |
MORI HIDEYASU
SANO YOSHIICHI
KOMURO ISAKU
