View Full Version : Not receiving trunk events

06-29-11, 10:29 AM

My application is interfacing with a Daytona Analog HMP PCIe 16T board.
The intension is to log POTS phone-lines in passive mode.
Therefore each trunk channel is connected in parallel with a phone-line.

Besides passive logging of the phone-line, I am also interested in detection of some phone protocol events, i.e. on/off-hook and on/off-ring events. It is the reception of those events that malfunction:

No trunk on/off-hook events are received.
Are these events only generated as response on a SetHookSwitch command?
Only sometimes ring-on/off events are received while the phone is ringing.
The ringing signal is generated by a company phone system. The ring signal is about 100 Volt top-top, with an average voltage of 0 Volt (so a pure AC-signal).
Why is not each ring signal preceeded by a ring-on and terminated with a ring-off event?
Thanks for any answer(s).

06-30-11, 11:07 AM
Hi schellens,

When connected directly to the telco SetHookSwitch is the only way to exercise on/offhook.

As for the failure to get the expected trunk events when logging, have you made sure to set the line threshold correctly? I suspect this could be the problem. Specifically - to use the board in a passive logging scenario it is necessary to use the PKH_TRUNK_SetThreshold function and set either PKH_TRUNK_THRESHOLD_24V_LOGGING or PKH_TRUNK_THRESHOLD_48V_LOGGING depending on the line.

In aohtest I think the command should be:
"trunk 0-15 set threshold <value>" where normal=4, 24V=16 and 48V =33

07-01-11, 02:26 AM
Hi mrecoskie,

Indeed the use of threshold passings (in my case THRESHOLD_48V_LOGGING setting) also works to detect on/off-hook changes. I just was wondering why the "real" on/off-hook events are not received in passive logging mode.

Any ideas about the inconsequent reception of ring-on/off events?
May the absence of a 50V bias-voltage (only a pure AC voltage is generated) be the reason?
In fact I receive a lot of REVERSAL events when the ring signal is generated.

Jan Schellens

07-11-11, 03:53 PM
The absence of a bias voltage should not be a problem. Is it possible to list the events you are receiving and their timings?