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Caller ID Encoder/Decoder Software for Texas TMS320C54x/C55x DSPs

This software implements byte transmission and reception for standard Caller ID (or CLI - Calling Line Identification) over local loops. The software consists of 4 routines:

CLI-ENCODE - calculates the checksum and sequences the bytes from a buffer loaded in the user code and transmits by calling:
CLI-TRANSMIT - generates each transmit sample, performing selectably either ITU V.23 (1300Hz Mark, 2100Hz Space) or Bell 202 (1200Hz Mark, 2200Hz Space) frequency modulation at 1200b/s, initially sending mark carrier for a user-set period then adding start and stop bits to each byte with per-sample timing

CLI-DECODE - times for a user-set mark carrier period then loads demodulated bytes into a buffer and finally performs checksum testing, the carrier and bytes being detected by calling:
CLI-RECEIVE - accepts each receive sample, performing line signal, demodulation to V.23 or Bell 202, and start-stop bit and bit-center timing

The routines can be used with most CLI formats eg ETSI, US SDMF/MDMF, UK SIN 227. The only assumption is that the second message byte is the total number of bytes following, excluding the checksum byte which is last. Parameter formatting and de-formatting can thus be performed in the user code.

The byte buffer formatting is 2 per 16-bit word for efficiency in multi-channel use. The CLI-transmit and/or CLI-receive routines are available separately. Each function has an initialisation call and a per-sample main routine call and is re-entrant with memory offset-addressing for multi-channel operation. Sample rates of 8.0kHz and 9.6kHz can be selected.

Performance:

• SNR for 10^-6 error rate (flat channel) is: 12.0dB (Bell 202) or 12.5dB (V.23)

DSP Load:

For 8.0kHz sample rate - B is the user-set buffer size

Availability:

NOW - sale is under licence - integration support offered