Patent GB-679178-A (GB)
Title: Improvements in or relating to arrangements for giving information
Inventor: HEPTINSTALL DENNIS LEONARD
IPC: H04M15/00
Filed: 1948-10-12
Abstract: 679,178. Automatic exchange systems. POSTMASTER-GENERAL. Dec. 5, 1949 [Oct. 12, 1948], No. 26593/48. Class 40 (iv). [Also in Group XL (b)] Apparatus for producing one coded signal in response to the reception of another comprises two banks of photo-cells co-operating with a constantly driven disc or strip on which an optical representation of each input signal is associated with an optical record for producing the corresponding output signal. The input signal may represent a name code and the output signal the corresponding routing code or metering charge in an automatic telephone exchange system. In other applications the device is set up as a reference book in which the input signal selects an item and the output signal gives information about that item, or as a ciphering device or as a high-speed photographically printing telegraph receiver. To increase the capacity of the system, several discs, one of which is selected by a preliminary operation, may co-operate with the same banks of photo-cells. Alternatively, several discs can be scanned simultaneously by a like number of pairs of banks. Detailed operation.-The input signals are represented in the system described as four digit numbers arranged along the radius of a disc, Fig. 2. Each digit consists of four elements (21 ... 24) and each element occupies two spaces either of which may be transparent, the other being opaque. The marks for producing the output signals are arranged along the same radius and represent a six digit number. Each digit consists of four elements 25-28 and each element occupies only one space and may be opaque or transparent. A separate photo-cell co-operates with each space along the radius. Cells EPC1A, EPC4A and EPC1B ... EPC4B, Fig. 3, are the cells for the eight spaces of the first digit of the input signal. Switches EPC1A ... EPC4A are set in accordance with this digit and conditions are then such that when a radius with this first digit passes the photocells, all those that are connected up are blackened out. Similar arrangements are made for the remaining three digits and when all the digits on a radius correspond to all the digits of the input signal, none of the photocells EPC can conduct. When alignment is exact, a further photo-cell CPC is blackened out by the corresponding mark CS and a normally conducting tube 34 can no longer conduct and the anodes of photo tubes APC1, APC2, &c. corresponding to the elements of the output signal are given a suitable positive potential to enable them to conduct if they correspond to transparent code elements. Each photocell that conducts fires an associated thyratron T1, T2, &c., the anode relay of which thus registers the corresponding code element of the output signal. Modifications.-The use of other codes is mentioned or the same code may be used both for the input and output parts of the disc. The coded markings are not necessarily in line and may for example be in the shape of letters. The same disc may be used for answering a number of questions simultaneously.