| 摘要 |
<p>The first unit (1) contains a message generator (3) connected to a transmitter (4) with an antenna (5), and a receiver (7) similar in construction to the second unit (2). The second unit has a receiving antenna (6) and a memory (2-2), and is worn or carried as a thin card or a badge. For self-test purposes the transmission and local reception of the test messages by the first unit follow the same protocol as the normal communication between the two units. The test receiver (7) is preferably another card bearing a bar code.</p> |
