=== Parameters for Zaptel modules === (Note: this list is woefully incomplete, but is a starting point and will be improved as time permits.) --- VPMADT032 Parameters --- The wctdm24xxp and wcte12xp drivers support cards which can have an optional VPMADT032 hardware echo canceler module. If that module is present, the following module parameters are available for these drivers: vpmsupport - 0 or 1, defaults to 1 Enables or disables use of the VPM. vpmdtmfsupport - 0 or 1, defaults to 0 Enables or disables DTMF tone detection on the VPM (currently defaults to 'disabled' due to performance issues when this functionality is enabled). vpmnlptype - 0 through 4, defaults to 1 Selects the type of non-linear processor that should be applied when echo is detected and removed by the VPM. There are five choices: 0 - None (not recommended) 1 - Mute (mutes the echo) 2 - Random Noise (replaces the echo with random noise) 3 - Hoth Noise (replaces the echo with Hoth noise) 4 - Suppress (suppresses the echo to a specified level) vpmnlpthresh - 0 through 40, in decibels (dB), defaults to 24 Relative signal level of echo to transmitted audio at which NLP will be used to remove echo. vpmnlpmaxsupp - 0 through 90, in decibels (dB), defaults to 0 When vpmnlptype is 'Suppress', this value indicates the relative energy level decrease that should be applied to the echo signal). --- General Module Parameters --- latency - 3 to 32, defaults to 3 For the wctdm24xxp and wcte12xp drivers. Specifies the amount of latency the driver inserts into the voice conversation. On systems that are unable to service the interrupt in a timely manner, increasing the latency can decrease module init time since the driver will not need to dynamically grow the latency during initialization. However, the latency in the driver does add to the overall latency of any voice conversation.