NTT 600-A2 compatability with the HT802 ATA

[daniel_j]

Hey guys. I've recently become quite interested in rotary phones and have purchased a couple to use an an intercom in my house. I chose to use the HT802.
This is working great with my other phone, however my NTT 600-A2 is causing some confusion:

• This phone is a 20pps model, and I can't seem to find how to configure the HT802 to support this
• Dialing 1 on the dial produces 3 clicks, 2 produces 4, 3 does 5... I cannot find any information about this being a thing. Is my dial faulty in some way or did Japan use some other standard? See the below video for a demonstration
• I can receive calls without issue

Interestingly I cannot even produce an outgoing call when I use the autodial feature. I always just get a busy tone.

Any insight would be highly appreciated.
Thank you guys, your community has been a big help in my research so far!

[dsk]

Never seen a 20 ppt phone, and I believe that the ATA is not able to read those fast pulses. Not sure that even the pulse to tone converters do that either.  People complains to the need of accuracy to 10 ppt for most ATA's that accept puls dials. I have never had any trouble with my HT802.

[countryman]

I know nothing about 20pps dialing but it seems like this was a thing in Japan.I'm pretty sure no modern equipment is compatible with this standard.
Some dials have an extra contact to cut off 2 pulses to ensure a pause between two dialed numbers. This contact might be open circuit here.
Pictures of the back side of the dial would be interesting.

Edit, Hi dsk, you beat me by 45 seconds ;-)

[daniel_j]

Pictures of the back side of the dial would be interesting.

Here are some images of the back of the dial.

It would be very unfortunate if I couldn't use this phone with my ATA








I would think though this wouldn't affect the ability to make autodial calls or pulse the hangup manually? Both just produce a busy tone.

Is the 3 clicks for digit 1 etc a standard of some sort? It is nothing like I have found online

[countryman]

So if you go off hook you immediately get a busy tone instead of dial tone? I suppose by autodial you mean you programmed the ATA to dial a certain number as soon as the phone gets off hook?

I'm not familiar with this dial type. Looking at the 3 sets of contacts I would assume the lowest one is the pulse contact (opening the loop to submit a pulse), one of the upper ones is the off-normal contact (shunting the speaking circuit to prevent loud clicking sounds in the receiver) and the third contact should be the aforementioned cutoff contact, eliminating 2 excessive pulses.
As you have 3 pulses when dialing 1, possibly there is a problem at least with this set of contacts.

To address the dial speed, you could try to completely take out the governor spring if this is possible destruction free. Then see what happens. I do not assume there is a good chance to slow the dial down close enough to 10pps, but why not trying 

[TelePlay]

20 pps phones were used on switchboards, they were the WE 6E dial and it had a curved finger stop.

[daniel_j]

So if you go off hook you immediately get a busy tone instead of dial tone? I suppose by autodial you mean you programmed the ATA to dial a certain number as soon as the phone gets off hook?

Yeah I programmed the ATA to autodial a number after 5 seconds. When the 5 seconds hits its an instant busy tone. This also occurs when I dial anything. I do get a dial tone. It is also very possible I have misconfigured something, but it is the same config as the other phone that works.

I'm not familiar with this dial type. Looking at the 3 sets of contacts I would assume the lowest one is the pulse contact (opening the loop to submit a pulse), one of the upper ones is the off-normal contact (shunting the speaking circuit to prevent loud clicking sounds in the receiver) and the third contact should be the aforementioned cutoff contact, eliminating 2 excessive pulses.
As you have 3 pulses when dialing 1, possibly there is a problem at least with this set of contacts.

I will investigate to see if I can notice anything that seems wrong.
Could you please expand on what would be the governor spring here?

20 pps phones were used on switchboards, they were the WE 6E dial and it had a curved finger stop.

This is also what my research turned up, however it seems the 600-A2 also had 20pps, the A1 had 10pps. This information is from here .

[countryman]

I marked the governor spring with a red circle in your picture. Removing it will let the brake shoes rub against the brake drum at much lower speed, slowing the dial down.
I wonder if the 20pps dial only used a stronger spring or also a different gear ratio? In the latter case your chances would be really slim to get hold of parts to convert the dial to 10pps.

[TelePlay]

Here are some images of the back of the dial.

Your external links to imjur seem to be broken, they don't display on my computer.

We do not allow externally linked images becasue the links can go bad for several reasons over time.

Could you please create a new reply with the images attached and I will move them to the original reply.

Code Select Expand

[img]https://i.imgur.com/ullJQ04.jpeg[/img]
[img]https://i.imgur.com/KRWrrmH.jpeg[/img]
[img]https://i.imgur.com/l04Iajc.jpeg[/img]
[img]https://i.imgur.com/KbdbieF.jpeg[/img]
[img]https://i.imgur.com/OaPp01G.jpeg[/img]
[img]https://i.imgur.com/wUKgt9V.jpeg[/img]


[TelePlay]

I marked the governor spring with a red circle in your picture. Removing it will let the brake shoes rub against the brake drum at much lower speed, slowing the dial down.

That would be an interesting experiment.

That is not a typical WE governor in that the spring on this dial's governor is hooked around a silver post on each fly wing. The WE governor had a slit cut into each of the fly wings. This is a newer dial in that the gears are plastic and the assembly is held together with riveted posts, it's a throw away and replace with new type of dial unlike the early WE dials. Later WE dials were also made of plastic and rivets making them disposable when they went bad.

Not sure what removing the spring would do, create too much friction and slow the dial speed below 9 PPS or not provide enough friction to get it below 11 PPS.

The former would be preferable in that a spring with a bit of tension would be better than no tension.

daniel_j, do you have a way to test dial speed? Lot of topics on the forum dealing with both reading and adjusting the dial speed. That's in this board: 

https://www.classicrotaryphones.com/forum/index.php?board=25.0

[5415551212]

Instead of modify a 20PPS dial to 10PPS I would look at adjusting the intercom system to support a 20PPS phone extension.
There is a thread here on pulse dial ATA's
https://www.classicrotaryphones.com/forum/index.php?topic=20386.0

There also was another fella on here making his own Arduino based pulse to DTMF adapter, so with opensource hardware / software it is pretty easy to make the Ardunino detect 20PPS.  You could even use a DIP DTMF chip to do the heavy lifting of making DTMF.
I cant seem to find the thread, but it was from this year.
Cheers
--Stephen
   

[dsk]

To make tour own adapter had a thread here, and 20 pps was mentioned, but not how it ended.   https://www.classicrotaryphones.com/forum/index.php?topic=8425.0

[daniel_j]

Your external links to imgur seem to be broken, they don't display on my computer.

We do not allow externally linked images becasue the links can go bad for several reasons over time.

Could you please create a new reply with the images attached and I will move them to the original reply.

My apologies. I do not get the option to upload an image, insert image only allows me to enter a link. That is why I used imgur

I took the governor spring off and the ATA recognizes my dialed numbers correctly now. The dial is quite a bit slower than my other 10pps phone. Interesting that the HT802 tolerances allow this to work.

I must have a configuration incorrect because I still have the issue of no call being made to my other phone.

I'm sorry to have to link an external image again (I can't upload to the forum). These are my configurations for my two phones, FXS1 is the phone in question that cannot dial FXS2. When I dial any number on FXS2 it always calls FXS1:

FXS1: https://i.imgur.com/iUFpvnJ.png
FXS2: https://i.imgur.com/nRzZ9pP.png

Can anyone notice anything wrong here?

Back to the governer spring, I need to look into measuring the pulse rate further.
I appreciate you guys very much.

NOTE:  Click on images below twice to fully enlarge them for viewing the code

[daniel_j]

Here is the dial speed comparison to a 10pps phone with the spring removed

[countryman]

To upload pictures you need to click the "Reply" button under the last entry to the thread. Click on the text that I have marked red in the picture and follow the instructions. It is a quite straightforward procedure.

If you happened to start answering in the box that appears right at the bottom of each thread you will not find the upload function indeed. In this case, click the "preview" button and it will appear.

Great to hear the numbers are recognized now, for sure you will find a way to address the still existing flaws as well! Keep us posted...