"The phone is a remarkably complex, simple device, and very rarely ever needs repairs, once you fix them." - Dan/Panther
Started by Owain, January 29, 2012, 10:21:34 AM
Quote from: twocvbloke on August 24, 2013, 04:27:08 AMFor a dial tone, all you really need is something that plays a tone that you can identify as being the dial tone for the system, rather than being something like what you'd hear on a current landline or on something like a Panasonic PBX, and make it something different so other people can identify it as not being a landline dial tone... Though I don't think a "mains hum" dial tone as per the design of the system specifies would really sound good, it'd just sound like, well, mains hum, which makes phones sound like they're faulty...
QuoteShame you couldn't incorporate something like this though:https://www.youtube.com/watch?v=VzIXvO6RahQ
Quote from: GTC on August 23, 2013, 11:22:24 PMThanks for the tip regarding the 330 ohm resistor. I had it in mind to install a fuse in the ringer circuit. I may do both.
Quote from: DavePEI on August 24, 2013, 06:05:22 AMQuote from: GTC on August 23, 2013, 11:22:24 PMThanks for the tip regarding the 330 ohm resistor. I had it in mind to install a fuse in the ringer circuit. I may do both.No need to do both. If you encounter a short, or a shorted coil on a ringer, the 330 ohm resistor will present a proper load on the device, and protect it from damage.Dave
Quote from: Owain on August 27, 2013, 04:31:16 PMOh dear.If you get some wirewrap DIL sockets you can maybe spread the legs on them to fit the enlarged board; it'll look like a spider perched on the board but might enable you to use the 'free' board for a second module. http://www.rapidonline.com/cables-connectors/wirewrap-turned-pin-dil-sockets-truconnect-63770/
Quote from: GTC on August 24, 2013, 05:00:42 AMI agree with what you say about mains hum, and I'd love to have a modulated tone a la exchanges, but I'm looking for a simple solution. I'll probably just use a simple oscillator.
Quote from: Owain on August 28, 2013, 10:59:02 AMAudio store/replay chips/modules are so cheap now, especially as you only need a second of tone and can loop it, that you could easily capture some dialling tone from somewhere.For a rather comprehensive recording of British telephone tones, listen tohttps://www.youtube.com/watch?v=rYa9DPgWSk8At about 7' there is interrupted 50Hz AC as a ringing tone on a small railway PAX
Quote from: twocvbloke on August 28, 2013, 11:08:21 AMI like the doorbell dial tone...
Quote from: Owain on August 29, 2013, 03:21:32 AMI think it would be nice to built the relay PBX actually as designed; it's kinda vintage in its own way.