Patent GB-110339-A (GB)
Title: Improvements in Telephone Systems.
Inventor: SYMES HENRY
IPC: H04M17/02
Filed: 1917-01-30
Abstract: 110,339. Symes, H. Oct. 10, 1916, [Convention date]. Hiring telephones. -- A coin-freed set for an automatic exchange telephone system can be adjusted so that it can be worked without coins, or so that the caller alone pays, or so that the caller and receiver both pay, but not necessarily the same amount. The device receives two or more coins and can be set to operate with different numbers of pence or half-pence or both. An emergency slot to receive a small silver coin is provided. The impulse-sender A controls the circuit passing from line L<1> through the rheostat R, impulse contacts A<3>, contact B<1> closed when the switch hook is raised, to line L<2>. Bridged across the terminals R<1>, R<2> of the rheostat is the local microphone circuit, which passes from the microphone (not shown) to terminal 4, rheostat R<1>, R<2>, contact E, and thence to the joint J either (1) through switch 7 if the set is to be used without coins, (2) through contact F closed by a silver coin in the emergency slot T', (3) through a contact D, closed by coins in the slot P', and contact C' of the fraud-preventing device, or (4) through a contact K closed by a sliding member M operated by an extension B<3> of the bell hammer B when a call is received. From the point J the circuit passes through the primary of the coil I and the terminal 1 back to the microphone. The receiver circuit includes the terminals 2, 3, the condenser C, and the secondary of the induction coil. If received calls are to be free. the switch 6, Fig. 1, is moved to prepare the microphone circuit, which is completed at contact K when the member M is moved to the right by the bell. The member M is returned to its normal position by the engagement of a plate M<3> with a cam A<1> on the impulse-sender when the latter is operated. When received calls are to be paid for at a reduced rate, the switch 6 is opened and the hinged part M<1> turned into its horizontal position so that, when a call is received, it is moved into the slot P<1>, with the result that less coins need be inserted to close the contact D than is the case when a call is made. Coin action, multiple-coin. - The coins in the slot P, Fig. 4, are supported by the forked extensions of a member 0 pivotally connected to the switch hook, and control a contact-making lever D, carried by a bracket D<1> which can be adjusted vertically so as to determine the number of coins necessary to close the contact. The lower extension O<11> in the slot P' is arranged centrally so as to arrest a half-penny HP, as shown in Fig. 3, but the upper extension O<111> is arranged at the side of the slot so as to arrest a penny P, Fig. 2, but to allow a half-penny to pass. Thus, with the bracket D<1> set as shown in Fig. 2, the contact D can be closed by a penny followed by a half. penny, or by three half-pennies in succession, but not by a half penny followed by a penny unless a further coin is added. A third extension O<1> of the member O forms a stop for a single threepenny piece in the emergency slot T<1>. Fraud-preventing.-The lower end of a pivoted metal guard R is pressed out by a passing coin, thereby causing the upper end to pass across the slot so as to prevent a coin being lowered by a thread. The movement of the lower end of the guard also opens a contact C' in the microphone circuit.