| 摘要 |
PURPOSE:To protect the secrecy of content of communication by keeping the general function of a radio system as it is and inserting a privacy call circuit to a talking to a specific party only so as not to be intercepted easily. CONSTITUTION:Identification circuits 9, 9' are circuits applying identification and control to add or release automatically a privacy call function, and the identification circuit 9 decides that a group number for call is coincident or not with a specific call group number for predetermined privacy call, and when the numbers are coincident, circuit operating privacy call circuits 8, 8' are activated, and inactivating them when dissident. The identification circuit 9' uses one of two group numbers for incoming as a specific incoming group number for privacy call, activates the pricacy call circuits 8, 8' when the received group number is coincident therewith and inactivates them when dissident. Through the constitution above, talking is applied to a specific party decided in the specific group number through the privacy call circuit, and a conventional talking is applied to parties of other group numbers without the privacy call circuits and the equipment is used safely for business purpose effectively. |
