A point-of-sale terminal (1) has a removable control circuit (20) upon which is mounted a separate and removable communications circuit (21). A printer (25) is mounted over these circuits by use of bridging supports (26). Control, communications and printing functions of the terminal are easily interchangeable because of the signalling and mechanical interconnections. Openings (12) in the base of the terminal (1) are blanked out by blanks (46). The terminal may be converted to a portable unit by insertion of galvanic contacts in openings (12) for connection to battery charging probes in a fixed cradle which communicates with an authorization processor. For this mode, the communications circuit (21) is a radio transceiver for radio communication with the cradle.
