Abstract: A data communication control apparatus for use in association with a facsimile transmission device, comprising: a memory for storage of telephone number data, private network protocol information and telephone line communicable data; an off-hook detector for determining when the facsimile device is placing an outgoing call; a controller for controlling the outgoing call in response to an instruction from the off-hook detector, the controller comparing the number of the outgoing call with the telephone number data in the memory and determining whether that number is served by the private network; and a fax-tone detector in association with the off-hook detector and memory for determining the time-out parameter of the facsimile device placing the outgoing call; wherein when the outgoing call is placed by the facsimile device, the off-hook detector instructs the controller which first determines whether or not the outgoing call is a long distance number and, if so, whether the long distance area code is serviced

Abstract: An improved alarm security system is disclosed which provides caller identification information when an alarm panel completes a telephone communication with a central computer. Such information is automatically provided by the telephone network upon initiation of a telephone communication. The central computer can use this information alone or in combination with other information received from the alarm panel to improve reliability and provide a more effective security system.

Abstract: This invention relates to a piston ring having two ring elements and a spacer-expander the latter including a series of interconnected parts each comprising two pairs of inwardly directed limbs, the inner ends of which are in contact with and resiliently load the ring elements, and a spacer element which extends transversely to space apart the ring elements at the outer periphery.