| Home | Terms of Use | Site Map | Contact Us |
IndustryCommunity.com > Electrical and Electronic Community > Analog Circuit Design Forum > Message
Main Menu

[ List Subjects ][ Main Page ]
[ View Followups ][ Post Followup ]

Subject: Re: automatic off-hooking of phone when it rings

Date: 05/24/02 at 7:58 AM
Posted by: Russ Kincaid
E-mail: russlk@yahoo.com
Message Posted:

In Reply to: automatic off-hooking of phone when it rings posted by Akwasi on 05/23/02 at 3:25 PM:

The ringing is an AC signal which you can detect, then it is only necessary to draw DC current to take the phone "off hook". I don't remember the minimum current needed, but 30 milliamps will do it. The "on hook" voltage is 48 volts DC but the loaded voltage depends on how far you are from the central office. A constant-current load is therefore best to use.

Follow Ups:

Post a Follow-up:


Message to Post:


1999-2001 Sunlit Technology Co., Ltd. All rights reserved.