Usually all the buttons are scanned in a matrix from the microcontroller, so neither side of the switch will be at ground or v+ and is likely directly connected to the processor with little or no protection
__________________________________________ Ken Brown Information Systems and Communications Manager 905 829-0292 ext 233 -----Original Message----- From: Richard Kwok [mailto:[email protected]] Sent: October 17, 2009 10:41 AM To: [email protected]; Toronto Asterisk UG Cc: [email protected] Subject: Re: [on-asterisk] cheap door bell ip phone Thanks Ken. Yes I would need the microphone too. I also thought about your solution too but then I have to hang a phone on the outside. I would prefer having just a face plate with one button on it. Those one-button phone costs an arm & an leg > US$400... I am not sure how delicate the circuitry is behind the redial button (anyone knows?), but i agree that having a relay should protect it... Rich. ----- Original Message ----- From: "Ken Brown" <[email protected]> To: "Richard Kwok" <[email protected]>; "Toronto Asterisk UG" <[email protected]> Cc: <[email protected]> Sent: Saturday, October 17, 2009 10:15 AM Subject: Re: [on-asterisk] cheap door bell ip phone > Maybe the microphone too :) > > The redial button might forget the number after a power cut. If the phone > can be programmed to autodial a number, wire the speaker button instead. > > Since the circuit for the button wasn't intended for external use, it > might be sensitive to damage or may not like long runs. Consider mounting > a relay inside the phone and have the outside button control this. > > I ended up using an analog handset from the dollar store and an ata > programmed to dial an extension when the phone goes off hook. 3 years so > far on the original $10 phone outside. Keep it sheltered from the rain as > the wet connections may cause it to call you. > > Ken > Ken Brown, IS and Communications Manager, Dana Hospitality Inc. > > -----Original Message----- > From: "Richard Kwok" <[email protected]> > Date: Sat, 17 Oct 2009 09:54:05 > To: Toronto Asterisk UG<[email protected]> > Cc: <[email protected]> > Subject: [on-asterisk] cheap door bell ip phone > > Hi, > > I have been looking for a door bell phone and unable to find a cheap and > cheerful one. > > Any suggestion is appreciated. I am thinking of converting a simple $40 > ip speaker phone into a door bell phone by externalizing the 2 things on a > face plate to be mounted on the outside wall. > 1. the speaker. > 2. the redial button. > > After all, that's all it is ! right? > > Rich. > No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.422 / Virus Database: 270.14.20/2439 - Release Date: 10/16/09 18:39:00 --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
