Article View: sci.electronics
Article #4472Interfacing a phone - need small schematic
From: Jon Joshua
Date: Thu, 12 Apr 1990 16:07
Date: Thu, 12 Apr 1990 16:07
23 lines
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1333 bytes
I am building a hardware/software project for the MAC and I need some
help with the hardware part.
I need a small interface that hooks into a phone line and the Mac's
RS422 serial port. When a phone is off-hook the interface should
raise the signal on the handshake line. When the phone goes back
on-hook the interface should clear the signal.
From what I understand RS422 uses -1 and +1 and not 0 and 1 values.
Is this correct?
Thanks for any help.
JOn.
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<Apr.12.12.06.58.1990.7854@topaz.rutgers.edu>Path:
arc1-ca.pugleaf.net!utzoo!attcan!uunet!tut.cis.ohio-state.edu!ucbvax!agate!shelby!rutgers!aramis.rutgers.edu!topaz.rutgers.edu!jjoshuaShow Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!tut.cis.ohio-state.edu!ucbvax!agate!shelby!rutgers!aramis.rutgers.edu!topaz.rutgers.edu!jjoshua From: jjoshua@topaz.rutgers.edu (Jon Joshua) Newsgroups: sci.electronics,comp.sys.mac.hardware Subject: Interfacing a phone - need small schematic Keywords: neat-o Message-ID: <Apr.12.12.06.58.1990.7854@topaz.rutgers.edu> Date: 12 Apr 90 16:07:29 GMT Organization: Rutgers Univ., New Brunswick, N.J. Lines: 23