Patent GB-1400259-A (GB)
Title: Device for automatically establishing connections from a  sending station over a telecommunications network
IPC: H04M11/04
Filed: 1972-06-22
Abstract: 1400259 Automatic exchange equipment; substation equipment GYLLING & CO AB 22 June 1972 [23 June 1971] 29250/72 Heading H4K An automatic information sending equipment for connection to an automatic telephone network includes a pulse generator and a code setting unit on which both the number to be called and the information to be sent is coded. The equipment is preferably for alarm or suspension signalling and the occurrence is registered by contacts LAK connected to unit KE which causes bi-stable BFS to energize relay AR to energize the equipment. The equipment is controlled by program logic PL which causes line relay LR to connect the line connecting unit LA and thus loop the line L. The program counter PRB is stepped to output OE so that signal receiver SMT can receive dial tone, with a set time, to step PRR to output RN and enable the dialling sequence. Pulses from the multivibrator AF are applied to counters in the code setting unit NK which provides the correct number of pulses to be sent on the line by means of a pulse relay in connecting unit LA. When the number has been dialled the counter PRR is stepped to position SD when monostable multivibrator MFSD1 is enabled to send ringing signals on the line. When multivibrator MFSD1 restores, MFSD2 is enabled to restart multivibrator AF and modulate the tone sent by oscilltor OSC to the line until multivibrator MFSD2 restores and stops counter PRR to position 01. The line is again monitored by receiver SMT until a response signal is received when counter PRR steps to ITS and the coded information relating to the particular contact LAK that has operated is sent as pulsed tones. When this is sent receiver SMT is again connected to the line to await a stop signal which on arrival causes bistable BFS to be reset and all the counters restored. If during the operation of the equipment a tone is not received, within the allowed time, the equipment restores to its initial stage and counter SR is incremented. The number of allowed attempts can be set into counter SR by slider SRK and when this number is reached the equipment is shut down and disconnected from the line. The code setting unit comprises a first set of conductors which can be selectively interconnected with a second set of conductors. A first counter marks a conductor of the first set whilst a second counter is stepped in response to the output of multivibrator AF to mark in turn all the conductors of the second set whereby a pulse train is transmitted to the line. The first conductors are grouped with a first group corresponding to an area code after which a delay may be needed to receive a further dialling tone, hence the provision of step OH on counter PRR. The second groups is the subscribers number which is sent when PRP is at step AN and is followed by a pause to receive a response before the last group, consisting of the information, is sent. It is suggested that cards may be used to give the various sequences. Signal receiver SMT may be made responsive to voice signals.