albert@ucbarpa.Berkeley.EDU (Anthony Albert) (12/20/89)
I'm looking for an easy to implement way to detect the receiver off-hook warning tone. Apparently it is made up of 1400 + 2060 + 2450 + 2600 Hz tones that pulse on and off for .1 sec. Are there chips that do this sort of thing? Can I be guaranteed that phones left off the hook all over the US will receive this tone? What books and/or sources are there that deal with telephone electronics? Sources for things like special purpose ICs and anything else specific to telephones. Thanks, Anthony Anthony Albert ..!ucbvax!ucbarpa!albert albert@ucbarpa.Berkeley.EDU Anthony Albert ..!ucbvax!ucbarpa!albert albert@ucbarpa.Berkeley.EDU
wordy@cup.portal.com (Steven K Roberts) (12/22/89)
The DM8880 from Mitel Semiconductor handles all that... for info,
contact their sales office in Florida at 407-321-9880 (Tom Hamlin)
Chers...
Steve Roberts
Nomadic Research Labsdalyb@godzilla.UUCP (Brian Daly) (01/04/90)
A good general reference for telecommunications is:
Telecommunication Transmission Handbook
Author: Roger L. Freeman
Publisher: John Wiley and Sons
Brian K. Daly
AG Communication Systems, Phoenix, Arizona