SYSTEM FOR PROVIDING TELEPHONY AND DATA SERVICES

A telephone on-hook/off-hook state communication system (1) comprises a first part (40), for example in the form of an In-Line Analogue POTS presentation Adapter, which is operable to interconnect between a telephone apparatus (50) and a pair of conductors (242,245), and a second part (300) operable to interconnect between the pair of conductors (242,245) and a telephone adapter unit (32), the first part including a variable impedance (42) and means (43) for changing the impedance of the variable impedance (42) such that a property of the impedance at a predetermined frequency (f) greater than zero changes in response to the telephone apparatus (50) transitioning between an on-hook state and an off-hook state, the second part (300) including a detector for detecting the change in the impedance of the variable impedance (42) of the first part (40) via the pair of conductors (242,245).