| 摘要 |
<p>The telephone dialling codes in this system for automatic replay of stored codes, are recorded on a drum of magnetic material by a magnetic head. The dialling relay contact of the telephone operates a slave contact which switches the head between two voltages. During recording, the telephone is disconnected from the line. When a prerecorded code is played, the head energises an amplifier which causes the slave contact to transmit the code to the telephone line. The advantage of this system is that the dial of the telephone is used to record the stored codes.</p> |
