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Coin Tone

Overview

The Coin Tone feature is supported by the DSP-ONE card. It detects Coin Tones from pay telephones for the nickel, dime, quarter, and dollar. Coin Tones, including their timing and bandwidth specifications, are detailed in TR-TSY000456.

Avoids False Coin
Tone Detections

The Coin Tone feature is capable of avoiding false Coin Tone detections caused by speech input, by detecting no more than a cumulative $1.00 when exposed to the DTMF talkoff test suite specified in TR-TSY000763.

Resides on
the DSP Chip

All detection, cadencing, and discrimination of Coin Tones is performed on the DSP chip. Each DSP chip can service 20 simultaneous channels of coin detection.

Enabling the
Coin Tone Receiver

Coin Tone detection is enabled by sending the DSP SIMM Configure message with function type Coin Detection (0x0F for µ-law, 0x0E for A-Law).

Requesting the
Coin Tone Receiver

The Coin Tone receiver must be requested at least 200 ms prior to the first coin being detected for initialization. When a Coin Tone receiver is requested and there are no Coin Tone receivers currently available, the request is queued to a waiting list.

Attaching the
Coin Tone Receiver

The host application may attach a Coin Tone receiver to a channel by sending the DSP Service Request API message with a Service Type of Coin Tone Receiver. The CSP then starts reporting Coin Tone detections. When a Coin Tone is detected, the CSP sends a Call Processing Event to the host application that indicates the value of the coin dropped, in cents.

Disconnecting the Coin Tone Receiver

The host application is responsible for disconnecting the Coin Tone receiver, by sending a DSP Service Cancel message. If the call is disconnected, the CSP releases the Coin Tone receiver.

Canceling the
Coin Tone Receiver

The host application may cancel a Coin Tone receiver on a channel by sending the DSP Service Cancel message with a Service Type of Coin Tone Receiver.

Timing Out the
Coin Tone Receiver

In the DSP Service Request message, you can specify the maximum time for the Coin Tone receiver to be attached. The Completion Timer specifies the maximum amount of time to scan for Coin Tones. If the completion timer expires, the CSP releases the Coin Tone receiver. To disable the timer, set this field to 0xFFFF.

Digital Signal Processor
PCM and companding standard used in Europe to compress and expand the amplitude range of a signal before and after transmission. See µ-Law.