My C*Net / GPO Home phone setup - and wishes to improve it a bit!

[boombox]

The Brains of the operation
A Raspberry Pi running a slimmed down version of FreePBX.

The Adaptors
I have a Linksys SPA3000 and a Linksys PAP2T.

Tone dialling
Some Millman/Weber/Pillenwerfer/Cherkasskiy adaptors which fit inside the phones like this

The problem
I have significant bell tinkling going on. Now I don't know if this caused by the internet being so flaky at the moment with the Covid situation* or something else, but it's a real pain. It makes everybody in the house internally jump like the phone is about to ring...then it doesn't. It's quite low level stressful!
I also have very poor recognition of the no doubt perfect tones emitted by the converters by the Linksys ATAs. I did two test calls today and '4003' (the number of an internal extension) was received by the ATA as '400_' and '3003'. Frustrating!

So I have some thermistors on the way to hopefully help with the tinkling, but I saw a post by Andy which gave me pause. He talks about connecting his old Revelation PABX to his ATA to help with eliminating tinkling AND help with the pulse dialling.

Now I have an old Inspiration PAXB just sat on a shelf and I'm wondering if I really should be doing much the same thing - just wondering what the consensus is?

At the moment I can easily control all sorts of queues, ring groups, announcements, call flows using the FreePBX GUI (and the custom files where the GUI can't do everything) - I can also easily transfer calls between extensions - in adding the Inspiration to the mix I'd want to be gaining functionality really by adding in the Inspiration rather than losing anything.

Your thoughts welcome! Thank you!

* seems unlikely as the internet being flaky wouldn't cause the connection between the phone and the ATA to break, nor the connection between the ATA and the Raspberry Pi to break, so re-registering, which I think is the root cause of the tinkling, shouldn't be necessary?

[ThePillenwerfer]

Your system is way beyond my experience and understanding but I can say that I have a Linksys PAP2NA which has no problems decipering tones and only tings if it or the router is reset. Maybe there's a difference between the T and NA versions.

[dagskarlsen]

Never had that tinkle problem, but I have no English phones.
If nothing else works, this do! www.epanorama.net/circuits/tele_privacy.html
More easy, making a bias-spring of a spring from a pen.

A capacitor across the red-blue terminals on the tone unit may help on the voice circuit. I have used 1.5 uF because I had that one.

dsk

[Graham G3ZVT]

Here's my iteration of the Weber/Pillenwerfer/Cherkasskiy adapter
(I must confess I don't know of Millmans contribution yet)


When I built it originally, I used a "proper" three-lead crystal with a pair of 20pF capacitors.

it worked absolutely fine dialing directly on my BT line and also on one of my ATAs bit on the other ATA consistently ignored some of the digits.
Using the ceramic resonators (without the caps) gave me no problems. Oddly the resonators worked out more expensive than the crystals.

You appear to be already using a resonator, so it's probably not your problem, but I thought I would contribute the anecdote anyway.

[Dave Moll]

Originally Posted by rambo1152

...the other ATA consistently ignored some of the digits.

I have a Grandstream (HT502?) that consistently ignores the final digit - but at least that is easily worked around by repeating the final digit so that it is the extra digit that is ignored.

[Pellseinydd]

I have heard of other occasions of telephones connected to Linksys ATAs 'tinkling' for no reason. Appeared to be caused by the ATA as problem went away when another ATA was used.

I wasn't aware that a Linksys ATA 'displayed' the digits it had received. Have you looked at the digits being received with a separate digit display tester?

With reference to the Grandstream HT502 - whilst they work with pulse dialling telephones, they are designed for use with US specification dials rather than those of the 'UK' specification. Whilst both specs use 10 impulses per second, the difference is in the 'make/break' ratio of each pulse. The US spec has a 40% make/60% break ratio whereas the 'UK' spec is 2:1 (33.3% make/66.6% break). If the UK dial is perfectly adjusted, the tolerance overlap seems to allow it to work OK. However if it is the slightest bit 'out', it seems to fail - sometimes only occasionally. Easiest thing is to 'tweak' the dial pulsing contacts to be very slightly closer. Thus they are nearer the 40% make. Worked every time for me and still seems to work with UK equipment that is expecting 'UK' pulses i.e. my electro-mechanical exchanges. I've been onto Grandstream as their latest firmware for the HT8XX range of ATAs now has a recently introduced setting 'Enable pulse dialling Yes/No' tick boxes and also has another recently introduced option ' Pulse dialling Standard/Swedish' . I've pointed out to them the 33.3%/66.6% ratio is used worldwide and also the 'reverse' New Zealand/Oslo numbering (as opposed to the 'reverse' Swedish numbering). Also pointed out the 'pulse dialling market' for vintage phones not just for collectors.

[Graham G3ZVT]

Originally Posted by boombox

I also have very poor recognition of the no doubt perfect tones emitted by the converters by the Linksys ATAs. I did two test calls today and '4003' (the number of an internal extension) was received by the ATA as '400_' and '3003'. Frustrating!

Which to my mind, casts suspicion on the dial itself.
Speed.
Clean contacts,
and most important, correct mark-space ratio, which is upset if there is insufficient tension on the spring that presses the trigger that rides in the toothed wheel that defines the pulses.

My "232" phone with said converter is used daily with no issues. The code was written in the US and presumably optimized for US dials, but I have found no issues with the various slipping-cam and trigger types I have.