rf@wu1.UUCP (11/06/84)
The following is a specification for a TWX central office
interface taken from a procurement specification I'm writing.
It's enough to convince you of the necessity for local data
telephone interfaces.
Uucp: {decvax,ihnp4}!philabs!wu1!rf Randolph Fritz
Easylink: 62905318 Western Union Telegraph
Telco: 201-529-6238 90 McKee Dr.
201-529-6221 Mahwah, NJ 07430
2.2.1 Terminal Interface.
The terminal interface has:
a. A power supply which provides line power ("battery")
to the terminal.
b. A current detector which responds to terminal "off-
hook" and dialing pulses.
c. A tone detector which reponds to Telex II tone dialing
(see Customer Provided Terminals for Western Union
Telex II (TWX) Service, "Tone Address Signalling").
Conveniently, the Telex II dialing tones are the same
as those used in the U.S. public telephone network.
d. A ring generator which provides a U.S. telephone
network ring signal.
e. A dial tone generator, which provides the dial tone
described in the Telex II terminal manual.
f. A call progress tone generator, which provides the
call progress tones described in Telex II terminal
manual. The tones are the same as the F2 tones of a
Western Union F1/F2 modem.
e. A Western Union F1/F2 modem. This is essentially a
Bell 103 modem.
g. A restraint tone generator, which provides the
restraint tones described in Customer Provided
Terminals for Western Union Telex II (TWX) Service,
"Receiver Characteristics" and "Automated Stop/Start
of Data Transmission."