Patent GB-303465-A (GB)
Title: Improvements in electric signalling devices
IPC: H04M3/64
Filed: 1927-10-04
Abstract: 303,465. Relay Automatic Telephone Co., Ltd., and Johnson, B. B. Oct. 4, 1927. Morse and like code signalling transmitting arrangements; impulse transmitters.-Relates to an electric signalling system wherein receiving apparatus such as lamps, bells, hooters, telephones &c. are operated by distinctive impulse codes in order to give a plurality of signals. The nature of the code, which may comprise one or more impulses or several groups of impulses which are variable in number, is determined at the transmitting station by the insertion of a plug into one of a plurality of sockets corresponding in number to the maximum number of signals and the particular signal selected is repeated until the plug is removed. As shown the receiving apparatus is intermittently operated by a relay D3 which is impulsed by an impulse generator I3 comprising relays 1 - - 4 under the control of a counting chain of relays C3 and a sequence control group of relays CO3. The code to be transmitted is determined by inserting a plug P3 into the corresponding socket, such as J2, to mark one or more of the wires MW2 associated with the back contacts of the counting chain C3. Impulse generation. When the plug P3 is inserted into a socket the ring contact rc3 earths the lead SW3 to energize slow-release relay 1 over the back contacts 1 of relays LI3, 4. Relay 1 causes the sequential operation of slow-release relays 2, 3, 4. Energization of relay 4 opens. the circuit of relay 1 to cause release of relays 2, 3, 4, the release of relay 4 again operating relay 1 to cause repetition of the cycle of operations. When relays 3, 4 are operated an impulse is transmitted to the counting chain C3 and relay D3, the impulse being terminated when relay 3 is released. Thus repeated operation of relays 1 - - 4, causes the generation of a series of impulses. Repeated signalling of a two digit signal. The apparatus shown in the Figures is adapted for the repeated signalling of a two digit signal, each digit comprising a maximum of five impulses. In order that the signal may be clearly distinguished, the series of impulses forming each digit are separated by a space which is of longer time duration than the space between successive impulses and each two-digit signal is separated by a space which is longer than the space between the digits. The number of impulses in the two series is determined by the plug P3 which appropriately marks the leads MW2. The first three impulses of a series operates the relays 1, 2, 3 of the counting chain C3 in succession. the fourth and fifth impulses re-operating relays 1, 2 while the relay 3 remains energized in the event of the generation of a full series. Upon the generation of the final impulse of a series as determined by a marking lead MW2, the relay LI3 is operated over a circuit including the lead tc3, tip contact of plug P3, appropriate marking wire MW2, back contact of relay in chain C3 which is responsive to the final impulse, lead IWLI3 to earthed lead SW3 over contacts 2 of relays 13, 3; 13, 4. Relay LI3 releases at contact 1 any relays in chain C3 which may be locked energized, terminates the operation of the impulse generator I3, and disconnects the counting chain C3 from the generator I3. At the cessation of the final impulse i.e., when relay I3, 3 releases, relay S in chain C03 is operated to energize relay 1 of that chain and consequently open the circuit of relay LI3 and disconnect receiver relay D3 from the impulse generator. De-energization of relay LI3 re-connects the generator I3 to the counting chain to count a number of impulses which have no effect on the relay D3 and thus constitute an inter-train pause. Upon the generation of the first impulse, which in the arrangement shown constitutes the pause, relay LI3 is again operated over the contact 2 of relay 003, lead IGW3 and back contact of relay S of chain C3 to stop impulse generation and release relays C3. Upon the cessation of the impulse, relay CO3, 2 is operated and relay LI3 is released. De-energization of relay LI3 opens a locking circuit for relay C03, 1, to re-connect relay D3 to the impulse generator relay ready for response to the second digit. The, second train operates the relay D3 and the counting chain until the relay LI3 is again energized over a circuit including the operated contact 2 of relay C03, 2, sleeve contact sc3 of plug P3, marking wire MW2 and back contact of the, appropriate relay in the chain C3. Relay LI3 energizes relay C03, 3 which disconnects relay D3 from the impulse generator and opens the locking circuit of the operated relays in chain C3 to cause its own release and consequently the regeneration of impulses for measuring the pause necessary between each two-digit signal. In the arrangements shown this pause is produced by three impulses which are then transmitted to the counting chain to again energize relay LI3 over contact 2 of relay C03, 3, and the lead ISW3 associated with the back contact of relay C3, 2. Upon the cessation of the third impulse, relay CO3, 4 is energized to cause, when relay LI3 releases, the release of relay CO3. 3 and in consequence the re-connection of relay D3 to the impulse generator. The apparatus is then in its initial condition except that relay C03, 4 is held operated in a circuit that includes contact 8 of relay C03, 1. This, however, has no effect and will release when the chain C03 is again operated by the following signal. Repeated signalling of single digit signals. The apparatus may be adapted for transmitting repeatedly a simple series of impulses, by connecting the lead sc3 also to the tip of the plug and connecting the leads IGW3, ISW3 to the same back contact of a relay in chain C3. Receiving apparatus. The receiving apparatus may comprise a number of lamps, bells or hooters or a combination of such. As shown in Fig. 4 (not shown), a number of telephones are connected in parallel and are operated by the back E.M.F, generated in the coil of an electric horn.