JX-002 Two Ways Extension Telephone Call Security Secret Keeper

Specification:

Description:

• Extension Telephone 2 Ways Security Call Confidential Device.
• Made by advance electron element. It can extend one exterior circuitry into two telephones to use (control by number of extension). And it can not increase the burden of circuitry of post office, each extension can listening and talking direatly.
• Between every extension, they always keep their work single, they don't break into the others, and keep secret while people talking.