The facility is intended to replace the Advise-duration-and-charge (A.D.C.) service available under manual working and is of particular interest to subscribers ... Meter pulses are transmitted over the subscribera#39;s line at a frequency of 450 c/s.
|Title||:||Telex: a detailed exposition of the telex system of the British Post Office|
|Author||:||Roy Worth Barton|
|Publisher||:||Pitman Publishing - 1968|