No Caller ID on the (a)phone or the (b)Sentry.
-(a) If the phone is connected to Sentry ‘in series’, switch to ‘parallel’ using a phone splitter. -(a)(b) Household with multiple phones connected to a wall jack might have to remove a phone if the ringer equivalence number (REN) exceeds the service providers limit. Usually from 3-5 REN. REN are usually located on the bottom of the base of the telephones. -(a)(b) With DSL internet services, try removing the filter or adding extra filters to the line up (connect the filters back to back).