British double-ring circuit--is it possible to reproduce?

[batterymaker1]

I have a few British phones on this side of the pond, and I'd love to find a way to make them ring like they would on your side--that short, staccato double-ring.

Does anyone have ideas on cooking up a circuit that would substitute our single-ring with a proper double-ring? I'm more of a shadetree mechanic than an engineer, so I'm clueless when it comes to modern circuitry.

Bill

[Tim]

You'll need 17Hz AC at about 85 volts...................

[Nickthedentist]

Originally Posted by Tim

You'll need 17Hz AC at about 85 volts...................

...plus something to generate the correct British cadence that's Bill wants.

[AndiiT]

Hi,
One way to achieve UK ringing is to obtain something like a Minimaster3 electronic PBX - these often crop up on e-bay. The Minimaster3 is a 2-line 10 extension PBX which will work with standard two-wire POTS telephones.

To obtain the correct UK ringing cadence you can loop one of the extension ports to one of the exchange ports (providing that you do not have an exchange line connected to the unit in any way) and by calling the appropriate extension number from one of the other extensions the correct UK ringing cadence should be heard on the telephones connected to extension 21, 22 and/or 23 depending on the configuration of the internal ringing DIP switches.
I believe that each extension port on the Minimaster3 can support up to 4 telephones (i.e. REN = 4)

Alternatively if you can get hold of a similar PBX (it must be one capable of operating with two-wire POTS telephones) something like a BT Revalation, Pathway or Inspiration or a London 12, another route to go down may be one of obtaining a VOIP analogue terminal adapter and using this to drive one of the incoming exchange ports. Calling the VOIP line from an external telephone (mobile, landline) will then instigate ringing.

NOTE - The BT systems mentioned above other than the Minimaster require at least one terminal telephone for initial programming of the system also the Minimaster will support only Pulse (Loop disconnect) dialing at its extention ports whilst the Revelation and the Inspiration will operate with either Pulse or Tone telephones (I am not too sure about the Pathway though).

Information about the Minimaster3 can be found at the following link http://www.britishtelephones.com/mini3.htm
Information about other systems mentioned can also be found at this site.

Don't forget that if you are using some of the later plug and socket (PST) type British telephones that you will need to connect these via a Master Line Jack socket to get them to ring.

Regards
Andrew

[julie_m]

It's very easy if you are using Asterisk!

In /etc/asterisk/indications.conf:

ringcadance = 400,200,400,2000
dial = 350+440
busy = 400/375,0/375
ring = 400+450/400,0/200,400+450/400,0/2000
congestion = 400/400,0/350,400/225,0/525
callwaiting = 440/100,0/4000
dialrecall = 350+440
record = 1400/500,0/10000
info = 950/330,1400/330,1800/330

Note that this will give you the "modern" dial tone (as found on electronic exchanges). I haven't found the frequencies for the "purring" dial tone as found on old-fashioned, clicky-clicky exchanges anywhere (yet).

Finally, when connecting your phones to ATAs, you need to know that British phones don't have the ringing circuit capacitor in the phone; it's contained within the master socket. You need to add a 470nF/250V capacitor between pins 2 (the red wire) and 3 (the blue wire). (A master socket actually contains a 1.8µF capacitor, to provide enough oomph to make 4 phones ring; but you only need a quarter of that for one phone.)

[Station X]

ring = 400+450/400,0/200,400+450/400,0/2000

It's ringing current thats needed, not ring tone.

16 and two thirds or 17 Hz ringing hasn't been used for years and 25 Hz is now the norm.

Old fashioned dial tone was a 50 Hz square wave rich in harmonics.

[Herald1360]

ISTR the US ring is about the same overall length as the UK double ring, so presumably you could cobble up a little circuit to interrupt the ring voltage to the bell for a short time half way through each burst. It should be possible to power it from the actual ring signal provided the drive power needed is no more than another bell would take anyway. Hmmmmm......

Chris

[julie_m]

Originally Posted by Station X

It's ringing current thats needed, not ring tone.

16 and two thirds or 17 Hz ringing hasn't been used for years and 25 Hz is now the norm.

Old fashioned dial tone was a 50 Hz square wave rich in harmonics.

The "ringcadance" (sic) line is what sets the ringing cadence (as long as the phone or ATA actually honours it). The "ring" line sets what is actually heard in the caller's handset.

The frequency of the ringing current probably is less important: as long as the period is longer than the decay time of the bells, they'll both be sounding together anyway.

If you want to get a double ring on a PSTN line (without paying the phone company for distinctive ringing signals), it should be possible to use a simple R-C timer to interrupt the bell circuit partway through the single long pulse. As long as you don't mention it to anyone from the phone company

And thanks for the information re. dial tone; I'll try 50, 50+150 and 50+250 and see what sounds the best.

[Tim]

Maplins used to sell a box that could make a phone ring on que, for stage plays and such like. Not sure where you would get one now though. ISTR it would re-produce US and UK rings.

[dseymo1]

A 556 and a a handful of other bits should deal with the cadence. For stage use, I once made a ringer which used halfwave rectified 50Hz mains, which sounded OK, but I don't know if 60Hz /2 would be convincing.

[arjoll]

I designed a circuit for my dad when he used to do sound for plays - he had an old system comprising a motor, hand-cranked generator, lots of Meccano (!) and a microswitch which I redesigned with a 555 running as an astable, a 4017 decade counter and a set of DIP switches, so he could 'dial in' an appropriate cadence using the DIP switches and by adjusting the frequency of the 555. This drove a relay, and the ring current itself was generated by a module pulled from an old phone system.

[mikelect]

I noticed when I was in the USA a few years back I noticed that the hotel phones in intercom mode rang with a double UK type ring so I guess there could be some used equipment around that would do the job HTH

Mike

[kalee20]

I needed a circuit to generate the traditional ring-ring of a telephone bell, for a stage production. The pdf below is the circuit I came up with, operating from a 12V sealed lead-acid battery. It drives a conventional DC bell - although I had to put a snubber of 0.1uF and 22 ohms across the break contacts, to stop radiated interference from affecting the CMOS logic.

The circuit has the refinement that operating the switch SW1 starts the bell cycle immediately - essential for the 'phone to ring on cue!

[batterymaker1]

Thanks for all the replies.

It'll be a bit before I do anything. A tornado went through my neighborhood last week!

We're fine, the house is only slightly damaged. Can't say the same for the homes up the road.

So, for right now, we're on the merry-go-round of insurance adjusters and building contractors. Hope to catch the brass ring soon.

Bill

[davidw]

Best wishes Bill..sincerely hope all goes well for you.