[Asterisk-Users] OLD PA system.

[Bob Chiodini]

Thomas Kenyon wrote:
> John Novack wrote:
>   
>> Bob Chiodini wrote:
>>
>>     
>>> You might put 600 ohm/600 ohm matching transformer to isolate the
>>> port and the amp.  Should also maintain loop current if needed.
>>>
>>> Bob...
>>>
>>>       
>> FXO ports do not  generate loop current, they detect loop current from
>> the Central office.
>> Think of an FXO as  a controllable switch and matching transformer.
>> An FXO port will give Asterisk/Zaptel a red alarm without loop
>> current, so that probably won't work for a PA system that doesn't
>> supply battery.
>> What's wrong with using the (usually) unused sound card built into
>> many machines?
>>
>> John Novack
>>     
> Mostly it uses the wrong impedance, and I know I can probably get an
> impedance matching transformer, but I'm not allowed to spend any money
> that I don't need to.
> (Otherwise I'd have replaced the amp in the first place with one that
> didn't fall from the arc).
>
>   
Won't you still need to maintain the loop current to make the PAP2 look 
like the port is off-hook?  (FXS BTW)

I would think the impedance matching xformer falls int the "need to" 
category.

Bob...