| 摘要 |
<p>The present invention relates to a telephone call device and a method thereof, and in particular to an improved telephone call device that can lower a telephone call rate, when a call is made from internal extension caller to the external wireless phone, or from external wireless phone to internal extension receiver by using a separate, portable wireless gateway unit connected to the extension line, a switching control unit having a built-in exchange for directly accessing wireless communication network without having to interface with PSTN(public switched telephone network).</p> |
