After adding a phone number into memory, when you dial it, the device still allows it to ring once before disconnecting. Is there any way to stop it from ringing the caller at all?
This happens sometimes because the user very close to their local Central Office Switch (CO) so the CO picks up the numbers as the user dials them, and completes the calls before the device can cut off (e.g. disconnect) the calls.
Can I disallow all outbound calls except a few?
Yes, you can ... To disallow all calls, simply add \* to the disallow register 05, as follows:
How can I do a hardware reset?
Please look at the picture below. The two pads marked with red arrows need to be shorted when the phone is off hook. Keep pads shorted until you hear a beep, you are now in program mode and may enter the default programming code 88 ##.