[asterisk-users] X100M never goes on-hook state

[John Novack]

You need to replace the FXO module
Was there ever any sort of protection installed for the module?
Not what your carrier provides, that protects their equipment, but any 
secondary protection?
These modules are easily damaged. I know of one connected to a very old 
SXS switch that damages from a small inductive kick when it opens ( goes 
on hook )

John  Novack


Marlon Dutra wrote:
> Hi guys,
>
> I've been experiencing a very strange issue with my Digium Card TDM400
> as of this week. It has two FXS and two FXO.
>
> The FXO modules (both of them) never goes on-hook after hanging up in
> Asterisk. It had worked perfectly well for over four years.
>
> I put an ammeter in series with the line and the card, and immediately
> after plugging the connector to the card, I got 26mA in the circuit and
> a dial tone from the carrier, where it should be zero amper (on-hook
> state).  If a Dial() something, it works perfectly. I can Hangup() the
> call, freeing the channel in Asterisk, but the hardware keeps off-hook
> forever, locking the line. If I Dial() again, Asterisk opens the line,
> sends the DTMFs normally, but it doesn't work since the carrier thinks
> I'm still holding the first call.
>
> It behaves exactly the same way with another analog line. If I plug
> either of the lines and my other Digium card (TDM2400), it works ok. The
> same with my Brazilian DigiVoice FXO card.
>
> Ok, you all might say: your card is damaged, throw it away. Ok, I could
> do it, but now comes the funny part:
>
> If I put an DSL filter in series with the line and the card, IT WORKS
> PERFECTLY!!! The filter imposes 25 ohms over the circuit. Maybe that's
> causing the card to work. When I put the filter and the ammeter in
> series, I get zero amper when on-hook and 26 mA when off-hook, that's
> the expected behaviour.
>
> I'm not an expert in electricity, so I really don't know why the card is
> behaving that way. What does that resistance make for the card to start
> working ok? I know the DSL filter isn't only a resistor. Maybe it has
> another electrical component that's helping more than the resistor. Just
> a guess.
>
> Tomorrow I'll buy a 30-ohm resistor, take the DSL filter off, and test
> the card only with the resistor, to check it out.
>
> In order to isolate the problem even more, I plugged the FXO port in one
> FXS port. Immediately after plugging it, Asterisk announced at the
> console that someone went off-hook at the FXS port. So, it's not really
> a carrier issue. The FXS port is perfectly -48V on-hook, and about
> 20 mA in the circuit when off-hook, closer than the carrier to the
> standard values.
>
> Any clue is welcome.
>
>   

-- 
Dog is my co-pilot