Software for Telecoms & Audio
V.25 Modem Function DSP C Code
implements the ITU function V.25 for data modems. This is the 2100Hz auto-answer
sequence sent from the answering end at the start of a PSTN modem connection.
As well as audibly denoting a far-end modem in answer mode, the 2100Hz
signal automatically disables network echo suppressors and, if periodically
phase reversed as with the code here, also network echo cancellers.
Interfaces: at the sample interface, the code can operate at 8.0kHz and 9.6kHz sample rates, tx and rx sample transfer being simultaneous. At the control interface, the code has control word access to set V.25 segment durations, to sequence operation and to set operating parameters such as data size, and one diagnostic word to convey data transfer status such as V.25 progress.
- #example figures from compiling for the TI TMS320C5000(C55x) DSP processor
Availability: NOW - sale is under licence - integration support offered