Sam's Telecomms Documents Repository
Sam's Telecomms Documents RepositoryMost of the documents are in Adobe Acrobat® Portable Document Format (PDF). To download the free reader go to the Acrobat Web site
I describe some of the documents as recreations. This means that I have scanned the text and used optical character recognition to create a word processed document. The images have then been scanned separately and re-inserted into the document prior to conversion to PDF. This seems to produce the clearest print with the smallest file sizes.
For a detailed description of why and how I've scanned the documents read my page About Scanning Documents and the following pages, Getting the best from the Scanner and Optical Character Recognition
Post Office N-DiagramsThese diagrams were used by Post Office technicians when installing or servicing instruments and small systems. The full range of subscriber's apparatus was covered. This is invaluable information for collectors wishing to restore items to working order.
I have scanned most of the collection and the results of this can be seen on the N-diagrams page
A list of some popular diagrams can be found here. With splendid help from Dave Roberts I have created a numerical listing of the diagrams with their full titles. Let me know of any errors or omissions,
Telegraph Information| Baudot Multiplex Type-printing System | Post Office Technical Pamphlet for Workmen B6. A clear explanation of how the Baudot system worked, orginally from 1919 and reprinted 1934. Digital recreation from an original in Bob Fastner's collection. 349kB |
| Creed Model 75 | An article by the late Alan Hobbs, G8GOJ, produced for the BARTG Magazine
Datacom.227kB |
| Creed Model 444 technical Specification | Creed pubilcation summarising the technical features of the Model 444 (GPO Teleprinter No 15) 1.1 MB |
| Eyeball Characters | An article by me on how to produce characters in punched tape that
can be read by eye. Produced for the BARTG Magazine
Datacom.[HTML] |
| Hughes Type-Printing Telegraph | Post Office Technical Pamphlet for Workmen B5. A short description of the operation of the Hughes Printing Telegraph, first published 1919. Explains the signalling method and how the sending and receiving ends are synchronised. Digital recreation from an original in Martin Loach's collection. 394kB |
| An Introduction to Teleprinters | and Punched Tape Equipment. Creed publication from 1958 with many photographs of current equipment, which was the Model 54 at the time. The 'new' model 75 gets a brief mention. Digital recreation. 2.5 MB |
| An introduction to amateur radio teletype | The definitive guide to amateur radio teleprinting written by one of the pioneers, the late Irvin Hoff, W6FFC. 188kB |
| RTTY The Easy Way | A guide to setting up an amateur radio teleprinter station. Fifth edition, edited by Alan Hobbs, G8GOJ. Published by BARTG 455kB |
| Quadruplex Telegraphs & Repeaters | Post Office Technical Pamphlet for Workmen B4. Part A explains the fundamentals of quadruplex working with step-by-step circuit analysis. Part B states the reasons for repeaters and lists the different types. First published 1919: reprinted 1936 with corrections to 1934. Digital recreation from an original in the collection of Martin Loach. 334 kB |
| Western Electric Duplex Multiplex Type-printing System | Post Office Technical Pamphlet for Workmen B7. Includes the Murray and Siemens & Halske Multiplex Systems. Detailed explanation of how the systems work and the gains in circuit capacity from using multiplex working. Digital recreation from an original in the collection of Martin Loach. 556 kB |
Railway Information| STC Selective SPT System | A description of the STC selective signal post telephone system. Describes the signalbox unit and the mechanical waystation telephone.0.79MB |
| STC Motorised SPT | The handbook for the motorised dialling version of the waystation telephone. 1.02MB |
| ETD Map Issue L | A map of the BR Extension Trunk Dialling network with numbering scheme from 1981. Last version on tracing film before conversion to CAD. 129kB |
| ETD Map Issue R | As above but Issue R from 1988. The last version ever produced. Note changes in the London area to incorporate the One Number Londond Exchange Scheme. 400kB |
| BR 13402 | Code of Practice for railway public address systems. Probably from the early 1950s. Facsimile of original. 58kB |
| Hixon Recommendations | Reprint from Railway World October 1970. Modified auto-half barriers are commissioned - The Hixon recommendations are embodied at existing barrier crossings. 190kB |
| Railway Signalling and Communications Telephony Part 1 Telephony Part 2 |
A text book produced in the 1930s from Signal & Telecomms lectures. Chapter XI, Telephony contains: Part 1 - Principles of sound, Transmitters and receivers, Induction coil, Sidetone, Magneto ringing, Switchboards, Automatic system. Part 2 - Traffic Control Systems, Lines, Transposition of Wires, Lightning Protection, Superimposition, Buzzer Telephones, Carrier Telephony. Part 1 265 kB, Part 2 559 kB |
| Plessey Post-Hixon AHB System Drawing 20747 Crossing Unit Drawing 20748 Signal Box Unit |
Telephone System for automatic half barriers at level crossings. Plessey technical manual for the post-Hixon system. A2 sized circuit diagrams marked with modifications post-1980. 1.2MB, 291 kB & 285 kB |
| Train Wires to the Horizon | Reprint of an article from Railroad Magazine, March 1947. Traces the history of telegraphy and its close association with railways. Particular attention on involvement of Baltimore and Ohio Railroad, who offerd Sam Morse a wayleave for his demonstration. Culminates with report of trial, revolutionary for the time, of FAX transmission to a moving train. (Yes, in 1947!) 646kB |
| 745 Telephone | Telephone CB weatherproof CB - vandal resistant. Plessey manual. 822kB |
| Block Telephone | LNER circuit of Block Bell and Telephone from 1930. Allows dual use of the single wire circuit for block bell and telephone. Courtesy of John Midcalf. See also Fig 185 on P9 of Railway Signalling & Communications, Part 2 above. 38 kB |
| Single-Needle Circuits | LNER standard circuits for Single-Needle instruments. Courtesy of John Midcalf. 151 kB |
| LNER Standard Telephone Circuits | LNER standard circuits for Telephone instruments. Courtesy of John Midcalf. 552 kB |
| ETL Signalbox Concentrator | ETL (later Plessey) signalbox telephone concentrator as widely used on BR Southern Region. Was later manufactured by Whiteley Electronics of Mansfield. Courtesy of Mike Tyrrell. 792 kB |
Technical Manuals, Maps & Other Documents|
3000 Type Relay Data Post Office data sheets on the 3000 Type relays. Introduction (80 kB) 1970 Data Sheets (3896 kB) BR copy 1980 Data Sheets (3091 kB) Courtesy of Paul Ebling | |
| Circuit Symbols | Description of scalable images of electromechanical circuit symbols in Windows Metafile format. Download the Zip file symbols.zip (141kB) |
| Cable Pressurisation | Post Office Notes for Internal Students, "A short appreciation of the need for the awareness by all staff, both internal and external, of cable maintenance methods and aims." [159 kB] |
| Dial Adjustment & Maintenance MAI No 25 MAI No 26 |
Dial adjustment and maintenance instructions for Trigger type (No 25) and Slipping Cam type (No 26) [816 kB and 1.2 MB] |
| Educational Pamplets Telephones 1/1 Telephones 3/1 Telephones 3/4 Telephones 4/1 Lines 3/4 |
Post Office educational pamphlets. An excellent introduction to telephony topics. Telephones 1/1: Local and Central Battery Telephones [1.1 MB] Telephones 3/1: Automatic Step System [442 kB] Telephones 3/4: Ordinary Final Selectors [240 kB] Telephones 4/1: Uniselector Mechanisms [1.0 MB] Lines 3/4: Protective Devices used in telephone and telegraph lines (eg fuse, heat coils etc) [1.3 MB] |
| Engineering Instructions T1012 Tester AT5422 |
Very few EIs remain in my collection, but I found this one by chance. It describes the Test Set usually installed at PABXs and small exchanges. [250kB] |
| PABX 3 Drawings SAW 81071 SAW 81510 SAW 81520 Notes SA 8153-1 SAW 81532 SAW 81581 Notes SAW 81582 SAW 81600 |
The circuit drawings for various parts of a PABX 3. SA is a schematic, SAW is a routed schematic with wiring instructions. Diagram Notes Courtesy of John Griffiths. SAW 81071 Ring & Tone [229kB] SAW 81510 Extension Line & Finder (ATE Dwg No TG1713 based on AT8151) [190kB] SAW 81520 1st Group Selector Diagram [118kB] Notes [35 kB] SA 8153-1 Final Selector, earlier version Diagram [92kB] Notes [36 kB] SAW 81532 Final Selector, later version [103kB] SAW 81581 Exchange Line Circuit, earlier version Diagram [225kB] Notes [49 kB] SAW 81582 Exchange Line Circuit, later version with pencil alterations for Railway use [194kB] SAW 81600 2nd Group Incoming & Enquiry Selector [116kB] |
| Telecommunications Instructions B2820 Keyphones F1011 Doric F1012 Harmony M0045 Card Callmaker |
Again very few of these remain in my collection. B2820 Keyphones Keyphones with Code C DC signalling. [82kB] F1011 Doric Amplifier and Loudspekaer No 11A, Doric [26kB] F1012 Harmony Amplifier and Loudspekaer No 12A, Harmony [145kB] M0045 Card Callmaker Marketing Instruction, Card Callmaker [140kB] |
| House Exchange System - Q-Diagrams | In addition to public exchange systems the British Post Office also supplied intercom systems under the title House Exchange System. It was documented in a series of Q-diagrams. A numerical listing of the Diagrams can be found here |
| Loudspeaking Telephone No 4 | User Instruction Card |
| TE & Loop Resistance | A 140. Transmission Equivalents and loop resistance of loaded and unloaded cable circuits. 30kB |
| Circuit Symbols | Description of scalable images of electromechanical circuit symbols in Windows Metafile format. Download the Zip file symbols.zip (141kB) |
| Cable Simulator | A friend built this along time ago to simulate PO cable types to assist with testing equipment. Component values and photos to show construction. [374 kB] |
| Dictograph Flyer Dictograph Explanatory diagram Dictograph Users Handbook Dictograph circuit for system with one master |
Dictograph office telephone systems: a promotional flyer and explanatory circuit diagram, both circa 1936, user's handbook (digital recreation), possibly 1950s, and a circuit for one master station and two subs, dated 1953, converted from a blueprint. Courtesy of my correspondent in Australia. [ 239kB, 512kB & 102kB ] |
| French PTT S63 Telephone |
Courtesy of John Mulrane a redrawn version of the internal paster label with English captions. [12 kB] |
| GEC Telecommunications, August 1956 Contents & photographs
GEC: New High Performance from Subscribers' Telephones |
Courtesy of Andrew in Australia, the contents page of the GEC house mag from 1956 & colour photo of the 1000 range [73 kB] Followed by the first of two articles describing the design behind the new 1000 range of telephones. [1.6 MB] |
| GEC 1000 Telephone |
The second of two articles describing this new introduction to their range of telephones, the 1000 model. [128 kB] |
| GTE Flip-Phone |
Original USA version of user instructions. [216 kB] |
| Pneumatic Protection of Telephone Cable Networks | An article about pressurisaiton of cables, probably produced by Drallim Ltd, with some of my photographs added. 67kB |
| Post Office Charge Groups | A map of the UK mainland showing the telephone groups on which charging was based. Created by staff on British Railways for their own reference purposes. |
| Lineman's telephone, No 704. | Installation and operating instructions 69kB |
| Plessey 745 | Weatherproof CB telephone handbook (as in Railways above). 800kB |
| Siemens Report W923, Motor Uniselector | Courtesy of John Mulrane. This is a detailed description of the construction and operation of the motorised uniselector as used widely in the PO trunk switching network. Excellent photographs. Dated 1934.646kB |
| TIM 2000 | A digital recreation of the good old-fashioned Post Office Speaking Clock with the voice of Pat Simmonds. [HTML] |
RecordingsThe singing operators - sound recording and lyrics from a GPO Film Unit short, The Fairy of the Phone [Picture: GPO]
Ethel Cain, also known as Jane Cain, the Golden Voice of the Telephone, and the voice of the first speaking clock, gives advice on diction for telephone operators. This is from an elderly 78 record, so please forgive the sound quality.[MP3 format, 4:46, 1974 KB] Picture: AP.
In the second part of her talk, Ethel Cain gives examples of good operating practice. [MP3 format, 4:30, 1870 kB]
Telephone 706 Bell rung with BPO standard cadence, .4s on .2s off .4s on 2s off. Contains a single ring cycle which when looped should sound like the good old days. [MP3 format, 3s, 22 kB]
The "Let's Take a Telephone to Bits" ProjectA new and long term project as I dismantle various phones in my collection. I comment on the mechanical, electrical and production design on each. The comments will represent my personal opinions and prejudices and not necessarily mainstream thinking. There will also be plenty of pictures. It's not intended to be a guide to restoration. I leave that advice to others. It's more like a Haynes® Manual with attitude.Let's take a Phone to Bits Index
Created: 9 August 2001. Recent Revisions: Phone to bits made separate page, Corrections Mar 2008. Creed Introduction, LNER circuits Apr 2008. Dictograph items and Technical pamphlets Jul/Aug 2008.
Telecomms Index