| 摘要 |
PURPOSE:To recognize exactly and quickly a trunk line during selection by transmitting selectively trunk line lamp display information and information representing a selected trunk line number from a master telephone set to a character display device provided to a key telephone system at an incoming call and lighting the display. CONSTITUTION:A key telephone system connected to the master telephone set is provided with a display control circuit 210 comprising a microprocessor. The operating input of a hook switch 214 and a trunk line and extension selection switch 211 is fetched, the presence or absence of a change of the input is checked, and when an input exists, the switch information (control signal) incoming via a data line 212 is fetched and when the information is a lamp display signal, a trunk line and extension display lamp 204 is lighted. When a trunk line number is incoming via the data line 212, the number display information is converted into character signal, fed to a display drive circuit 213 so as to display the character to a display circuit 205. Thus, the trunk line during selection is recognized quickly and exactly. |
