Sender test frames, one part of the first No. 4 crossbar switch, Philadelphia, 1943.
Milestones in AT&T Network History
About AT&T
|
Support
|
Careers
|
Toll Free Directory Assistance
|
Terms & Conditions
|
Privacy Policy
© AT&T Intellectual Property. All rights reserved. AT&T, the AT&T logo and all other AT&T
marks contained herein are trademarks of AT&T Intellectual Property and/or AT&T affiliated companies.
36 USC 220506
Hosted by AT&T and powered by
AT&T Content Acceleration
