[GreenKeys] Post Office Pamphlets for Workmen - B4 & B5

[Sam Hallas]

Two more in this series, thanks to a THG member for scanning his originals.

Pamphlet B4: Quadruplex telegraphs & repeaters. 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.

Pamphlet B5: Hughes Type-Printing Telegraph. 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.

http://www.samhallas.co.uk/repository/index.htm#Telegraph

Cheers,
Sam