My customer has a SX-200 EL/ML that they have to reset card to put back in use. This is a satellite system that receives calls from the main thru a T1/Adtran/PRI Card and the also have a LS Class card for local trunks. CID is programmed but not purchased thru their telco provider.
I'm not sure what is locking up the trunks but I have changed out the card and still have the trouble.
Most likely they are not getting any disconnect supervision or it is programmed incorrectly in the trunk attributes... Typically a disconnect of battery for a moment at disconnect (voltage goes to 0v for about a second, often called Positive Disconnect) or a tip-ring polarity reversal for about a second (caries by regulatory region, this sometimes is used for answer supervision in some parts of the world).
Put a buttset on the LS line and call in on it with a cell phone, have someone answer and put you on hold then hangup your cell phone. Within a couple seconds you should hear a distinct click (either a TR reversal or disconnect of battery) and the line should drop... If you don't get a Positive Disconnect signal, contact the telco and request a the line be provisioned with it. If you do get it, check the Trunk Circuit Descripter and pay attention to Reverse to Idle (for T-R reversal disconnect supervision, normally off), Ignore Remote Disconnect (make sure this is off), Disconnect timer (the default is usually fine, might have to lower slightly in some instances, lowering too much will result in random disconnects), and Supervision Direction. If in doubt on any settings, check the manual.
You may also need to make sure Impedence and loss/echo settings are correct.
