Any way to implement a phone dialer for sending alerts to a given phone number under conditions detected by a Rabbit C application - we want to notify certain parties by telephone of alarm conditions detected by our application (in addition to email alerts). Thanks much!
Otto von der Hoff
Sylogy Software LLC
Minneapolis MN
otto@sylogy.com
[QUOTE=ottov;607]Any way to implement a phone dialer for sending alerts to a given phone number under conditions detected by a Rabbit C application - we want to notify certain parties by telephone of alarm conditions detected by our application (in addition to email alerts). Thanks much!
Otto von der Hoff
Sylogy Software LLC
Minneapolis MN
otto@sylogy.com[/quote]
mmmhhhh and using pwm is not possible to make a tone dialing?
on an LP3500 you have a relay too, usefull to manage the connection.
P.S. is only an idea!
Marco
It seems to me that the easiest way to do this is to not try to implement the dialer within the microcontroller itself, but rather have it trigger a web-based script that does the phone dialing.
I suspect that Perl probably has some modules that support phone dialing (or, if not there are pay services with APIs you could access). One advantage to having the actual dialing handled outside the microcontroller is that it will be much easier to edit who gets the notification.
I was offering the simplest to implement solution, and if he’s doing low volume it means he doesn’t have to go through approvals for connecting to the phone line as the modem already has them. Secondly, it would require some filter and op amp components, and the proper magnetics to tie to the phone system. The tones used on phones are actually comprised of two frequencies mixed together so they are not trivial to implement on a pwm. If looking for an integrated hardware solution, I would recommend readily available dialer chips as another fairly simple solution. I believe most of these would only require the magnetics and not the filter and op amp needed to drive the signal from a pwm.
Hi, I don’t know if this is what you want but I have just used a phone dialler unit purchased from a security company (burglar alarms etc. about $100). It stores a 16 second voice message, will store 6 phone numbers which it will cycle through until it gets a response. You can set a shutdown code that the person receiving the call can punch into their phone keypad to acknowledge the call. You can trigger it with a TTL active low line from a digital output. It’s a simple solution if this is what you want.
The DTMF signals your looking to produce are sinusoidal, so unless modified through an inductive circuit etc. PWM would not be sufficient. Also, you wouldnt be able to just throw that sine wave at the phone lines and expect success, like mentioned there is some circuitry needed for that integration. I would recomend the $100 solution for something commercial, I have used one of those and they work really well. For a hobbyist solution I have tapped into a cheap desk phone and it took a 4066 bilateral switch chip for the pick-up switch, a 5089 DTMF tone encoder into the microphone, and a micro to do a pick-up and dial sequence, pretty easy but def a messy solution. Good luck!
The internet solution is not quite that easy. Somewhere there has to be the physical crossover from cyberspace to the public telephone system. Now that could be done through text messaging to cell phones which is often accessable through the cell phone providers website. This would of course require the storage of a web address and telephone number for each recipient unless you knew they were all on the same carrier. This might also require some additional programming depending on how the carrier accepts the messages. Putting the info through a normal GUI interface may not be that simple and I personally haven’t checked whether they have simpler API’s for electronically generated text messages.
There may be companies like Vonage or Efax which have the crossover equipment who could make a dialing service available, but then are you trying to send a voice message or more like a numerical page. If it’s a voice message, then you’re into VOIP which is much more involved. If paging, then if it is to a cell phone this again may be offered by the cell provider. Another option for dialing to pagers or cell phone paging is to use a stand-alone serial modem as your external dialer. Through AT commands you can dial the phone number, create pauses, and dial the return number or code you want to appear on the pager.