HT93214A Memory Tone/Pulse Dialer

The HT93214 is a dialer series with extendable features such as Lock function, keytone, and LCD Display Interface that is targeted for low-cost telephone set applications. It does standard Tone pulse switchable dialing and provides one-key redialing with a 32-digit memory for rapid dialing with a 4×4 keyboard. For precise timing, an on-chip Oscillator is included to work with an external 3.58MHz crystal or ceramic Resonator. The HT93214 has a Flash time of 300ms (F1 key) and 600ms (F2 key); tone dialing and a 10pps, 20pps option with 1/2 M/B ratio for pulse dialing; and tone dialing.

Pulse dialing was created to be a simple dialing mechanism that resembled a rotary dial telephone. This pulse dialing mechanism is technically defined by the phone’s rotary dial. The loop between the phone and the caller is broken when the caller picks up the receiver and operates the rotary dial. As a result, based on the number called, exchange at a certain frequency and at predetermined intervals. These disconnections are used by the analogue exchange switch to determine which phone number the subscriber phoned and are forwarded as current pulses to the so-called rotary switch. For appropriate signaling, a certain wait between the distinct numbers must be maintained.

The pulse approach is often supported by even analogue phones with push-buttons. Devices are frequently setup in a flexible manner for this approach and multi-frequency communication. Because the telephone number is broadcast over the speech channel and heard by the subscriber, this pulse dialling method is referred to as in-band signaling.