The 5XB Trouble Recorder
28:19
Malfunctioning Potted Relays: Emergency Repair in the No. 5 Crossbar
35:12
How does a No. 1 Crossbar work? - Dial Equipment Appreciation, Part 2
23:18
How many different ways can we cause trouble in the 5XB?
16:31
How does call tracing work? (Part 1)
50:17
Master Electronic Alignments!
22:40
"A MIRACLE FOR MRS. SMITH" HOW THE TELEPHONE WORKS WESTERN ELECTRIC BELL SYSTEM NETWORK 64414
19:03
The Machine that Makes Your Phone Ring
23:20