I have a customer using a Panasonic KTA-624 system in his rather large home. The main gate to the property is a very long distance from the house (mansion). When someone arrives at the gate they press a specific button on the keypad which will use a modem to access a specific phone line and dial the main number to the house. Inside the house the call comes in as a traditional incoming call. When the call is answered inside the house a code is entered on the keypad and the gate opens.

The problem the homeowner has is he can't open the gate until someone has opened the line from the gate location. In the current scenario if there was a circumstance inside the home where an ambulance was needed he would want to be able to open the gate by placing a call to the modem at the gate and then entering the code when it goes off hook. That way when the ambulance arrived the gate would already be open. This also would apply if the family were expecting numerous guests for dinner. The home owner could open the gate at 6:30 and eliminate the hassle of each guest calling the house.Currently the modem ignores incoming calls or at least it did for 17 rings.

Thanks for the future info!