Trunks that are operated with the feature described here must be answered or they will not be able to be released later. This condition does not apply if the trunk (including the hardware used) can handle forward release by interrupting the supply voltage. You must coordinate this with the remote exchange during the system start-up.

If forward release is not possible, you must set all intercept cases (COT) while keeping in mind that calls to the attendant console or night station must be answered. (One way to do this is with the help of an answering machine that also triggers when the system is operated unattended).