a signalling link interface in one arrangement the signalling link interface includes two intercept and transmit connectors and a coprocessor connector in one arrangement the communications processor includes a computer and a communications coprocessor the computer maintains a data base with tables of such data as invalid calling card numbers a computer program initializes and starts the communications coprocessor which handles high speed signal capture manipulation and high speed signal retransmission the communications coprocessor also interacts with the computer 39 s data base to alter table parameters application_number US 9666593 A description referring to the drawing and in particular to fig1 an open systems interconnection osi model is designated by reference numeral 10 and a signalling system 7 ss7 model is designated by numeral 12 ss7 model 12 includes an operation maintenance and administrative part omap 14 at least one application service element ase 16 a transactions capabilities application part tcap 18 or an integrated services digital network user part isdn up 20 or telephone user part tup 21 and signalling connection control part sccp 22 and three levels of message transfer parts mtps 24 26 and 28 respectively referring to fig2 the second level mtp 26 handles the signalling link functions the first level mtp 24 together with the second level mtp 26 provide a signalling link 30 between two directly connected signalling points 32 and 34 signal messages 36 and 38 are transferred over a signal link 30 in variable length messages called 34 signal units 34 there are three types of signal units in the second level mtp 26 differentiated by the length indicator field contained in each message the three types of messages are a message signal unit msu a link status signal unit lssu and fill in signal unit fisu referring now to fig3 and.