Rotatone vs Dialgizmo - Dial Hold features

[MCCAFFRP]

OK- Update # 2 for Halloween. I have disconnected the slate-red wire from the dial "R", isolated it, tested again and still no dial-hold features. I did try the wrong "R" wire last week. Then I put in the 220 ohm resistor between the phone and the Dialgizmo and also tried it between the Dialgizmo and the Ooma adapter as suggested all with no changes. The phone works the same - all dial tones are loud and clear and voice is loud and clear no matter if the dial shunt is in the circuit or not, resistor or none. I also checked the wiring of one phone thoroughly against the diagrams here including my F-1W handset (my phones are 302CW to be exact- as I found out with more research) The stamp on the base of my main phone is 4-38 and it has an aluminum shell. I will test the second Dialgizmo on this phone as well and will then swap parts and check wiring on the other phone and will post back again - just in case someone has some more ideas. I really don't get this. Could the dial be the cause of this? Would a different dial make a difference? Would a different pulse adapter work?

[dsk]

Sometimes I believe my suggestions are clear and understandable, but not. Maybe because of a "Norwegian" way of building a sentence.  I wrote : "It worked for me by  putting in a capacitor and a resistor in the line between the Dialgizmo and the exchange. (adapter)" and I meant something like this: (picture)
It is important to have a dial shorting the line when the dial is out of rest position.

dsk

[dsk]

An alternative idea could be to test the resistor in series with the transmitter, but this is something I not have tested, it is just an idea. This will definitely make a grater mismatch in impedance balance in the voice circuit.

dsk

[poplar1]

I recedntly purchased a Dialgizmo and cannot get the *, #, hold or redial features to work. I am using a correctly wired 302 connected to a Panasonic 616 KSU.

Does it work after disconnecting (and isolating) the slate-red wire on dial terminal R ?

I tried it with and without the slate-red wire connected; neither way worked as promised. Also, a 514 set doesn't.

[unbeldi]

Thanks for the red-slate wire tests, Poplar1 and MCCAFFRP.

This is as far as I am going to go with "fix" recipes, because it is the only obvious and easy test, and as I cannot test myself, not having a unit.  The only way to resolve this definitively is to take some measurements of line current, voltage, and resistances, and not take guesses.

The reports seem to vary about what works and does not.  I was under the impression that 500-sets do work. 500-sets do not short the loop completely, but dsk reports that this is actually necessary.  The 300-sets do so and don't work, that was the purpose of the red-slate wire test.  It provides the complete shunt through the off-normal dial contacts.

After measuring the line conditions before and during dial operation, I would open the gizmo box and monitor the supply voltage on the digital chips to make sure it doesn't collapse when the dial shunts the line.  This may be the crucial aspect in this and it could be highly dependent on the type of telephone connected, as well as the type of line the setup is connected to.

Has anyone reverse-engineered one of these, like we did recently for one of the Chinese Dialor models?  It should be similarly easy, I would think.

[MCCAFFRP]

Hello dsk,
Thanks for the clarification. Yes, I did understand what you offered before - but thanks for the note on actually needing the dial to shunt the line when using the resistor. The reason I tested with the slate-red line off was due to an article I mentioned previously in this post. It mentioned trying the resistor in line on the phone side of the Dialgizmo and then after that worked for the author, he disconnected the dial shunt and removed the resistor and that also worked. However when mentioning that it "worked" he did not make actual reference to what was fixed - whether that meant the basic dial tone function or dial-hold functions of the adapters he tested. I tried this with no changes to my results. Then I tried your suggestion of putting the resistance after the Dialgizmo with the dial shunt (slate-red wire) reconnected. I have added a 220 ohm resistor in series in the R and I have tried it both with and without the addition of a 1.5 microfarad non polarized cap. I used a ceiling fan cap as I didnt have that high a value in a smaller voltage rating. It made absolutely no difference in the voice volume or dial hold features. I tried to upload a photo but apparently I am not allowed yet. I have approached the forum admin and will post again when my account restriction has been lifted.

[unbeldi]

It made absolutely no difference in the voice volume or dial hold features.

It is very hard (~impossible?) to see how that in fact would make a difference to the operation of the gizmo. I like to hear the theory of operation of that recipe.

A resistor in the CO side w/r/t the gizmo in the loop only limits the current drawn from the central office battery. I do not see how that can effect the operation of the gizmo positively.  I would think that this is in fact compensated by the requirement of having the dial shunt the loop completely to make up some of the lost current during dialing.
The added capacitor only provides a lower impedance at voice frequencies, so loss of loudness when speaking and listening should be minimal.

[dsk]

The idea behind, and it worked for me was the idea; it seems like the power-supply to my line dos all it can to rise voltage until the current is 35 milliamps.  Trying different phones 2 in parallel... always 35 mA.   My idea was that the Dial gizmo had to know the difference between regular off hook, and rotating the dial and holding (before pulsing) since dial and hold was a way to tell the unit to send for instance a #.
My EB1953 has a circuit not shunting the transmitter (primary) winding of the induction coil. (it shorts the transmitter capsule, and the receiver) By moving one wire from the dial, it did not help, adding the resistor as I did in my sketch did not help, doing both, did work.

dsk

[MCCAFFRP]

Hello Unbeldi- I took measurements - Ooma telo on hook voltage (with my 302 connected) - 47.5v, 24.5 ma. Off hook voltage drops to 7.7 and when dialing drops to 5v. This is with the phone wired as it is supposed to be wired. (dial shunt in place) Wonder why the voltage drop when dialing? I almost expected it to stay the same. Help interpreting this would be appreciated. Also - I read somewhere online where someone else didnt have the dial-hold features and they were using the Obihai adapter and their fix was to raise the loop current (from 20ma to 30ma) and that got the extra features working. Apparently, the Obi units have a loop current adjustment. Could it be that my 24.5 ma. is just a bit too low for the Gizmo? I have been looking at loop current boosters, but most only boost to 26 or 27 ma. Thoughts anyone?

[unbeldi]

Hello Unbeldi- I took measurements - Ooma telo on hook voltage (with my 302 connected) - 47.5v, 24.5 ma. Off hook voltage drops to 7.7 and when dialing drops to 5v. This is with the phone wired as it is supposed to be wired. (dial shunt in place) Wonder why the voltage drop when dialing? I almost expected it to stay the same. Help interpreting this would be appreciated.

The voltage drops again when operating the dial, because the dial shunt switch kicks in and places a short across the transmitter and the induction coil primary winding.  This is the slate-red wire to the R terminal on the dial.  But I am surprised that the voltage only drops to 5 V, where did you measure the voltage?  Probably before the dialgizmo on the line side.  The gizmo needs to maintain that to keep operating, but it indeed could be effected by the dial.

Also - I read somewhere online where someone else didnt have the dial-hold features and they were using the Obihai adapter and their fix was to raise the loop current (from 20ma to 30ma) and that got the extra features working. Apparently, the Obi units have a loop current adjustment. Could it be that my 24.5 ma. is just a bit too low for the Gizmo? I have been looking at loop current boosters, but most only boost to 26 or 27 ma. Thoughts anyone?

Many or perhaps most SLICs, subscriber line interface chips or cards, have provisions to select from a range of loop current settings, usually these settings are not implemented in the web-based user interfaces, but when one gains access to the command line interface of the adapters, via telnet, ssh, or the console serial port, then this can often be adjusted.   I suspect that lack of current is the cause of failure in many instances.

[MCCAFFRP]

Hello Unbeldi-
Yes I took those measurements on the line side of the Gizmo. The current measurement was done both in series and also in parallel with no differences noticed. The reason I posted them here was so that maybe someone (Mr. Mike) or anyone else whose Dialgizmo Dial Hold features are working with an Ooma Telo unit might measure their voltages and share them here. I was hoping to learn something from the comparison as to why my DH features arent' working. As far as gaining access to the Telo via telnet - I can probably do that via its WAN port, but not knowing the specific commands and possibly an elevated command needed to modify firmware settings for the particular chip, I would not want to try that without specific direction from someone who has done this successfully. So far I cant find anyone who has done this on a Telo - or anything detailed about its design that would indicate an adjustment could be done. Comments anyone? Has anyone measured voltage and current draw on a Gizmo with a WE 302 phone connected to an Ooma Telo? Has anyone tried connecting a loop current booster - like the ones from Viking or Sandman.com?

[MCCAFFRP]

Ok- I can see this thread is now stale - as no one has replied in awhile- which probably helped me by forcing me to work things out myself. I  have an update to share - if anyone cares anymore. I had given up on the Dialgizmo dial-hold features and purchased a Rotatone. So I received it and reviewed the "instructions" and schematic from the guy's site and was confused about its proper install on my phone - so I started another subject and (which is still open.) What happened is that upon review of the schematic provided for the Rotatone, I reviewed the original WE diagram and went through my phone and made sure it was proper and took voltage and current measurements. I found that everything was indeed wired stock. I had Tip (green wire from CO) connected to L2 and Ring (red wire from CO) connected to L1. But when I measured across L1 and L2, the polarity was wrong. I checked my cables and connected directly to the Ooma Telo and measured again. It's polarity is opposite At&T in my case, so I switched the green and red wires and checked my on and off hook voltage and dialing voltage with dial shunt connected again. My off hook voltage is 3.5-4 v - which is low. When dialing my voltage is 0 due to the shunting of the entire phone, which is also not good. So what I did was move the dial shunt wire from L1 to R on the coil and checked voltage when dialing again. it is now .5V and I was able to use the dial-hold features of * and # by holding for 4 seconds but redial and speed dial didnt work. The Rotatone installation mentioned the unit needed at least 5 Volts and to install a zener diode to bring up the voltage if using the original transmitter, so I tried that. My off hook voltage is now 7 V and all of the dial-hold features work on my WE 302 phone, but I have to hold for 3.5-4 seconds! I have stored some speed dial numbers and tested redial, dialed # and * and all works properly. I don't really need the Rotatone now, but as soon as I can confirm its proper installation I am going to install it and test it's quality vs the Dialgizmo. I hope to be able to dial a # quicker than 4 seconds - as that seems too long for any modern systems to detect it, rendering it useless! I had heard that before, but I wanted things to work as advertised anyway! Thanks everyone for your input!

[unbeldi]

Sorry.... I'll catch up soon.

[MCCAFFRP]

OK - small glitch - I didnt test inbound calls after installing the zener and moving the dial shunt to "R". The ringer no longer works - but it is faint. I'll work on this and post my solution soon. But I might just move on to installing Rotatone now. Who knows.

[MCCAFFRP]

OK - the problem with my ringer had nothing to do with the zener diode, which I had installed in series in the green wire that goes from BK on the dial to the receiver to raise the voltage to the Dialgizmo. It was my wiring job that got in the way of the bell clapper. For people watching this post, this means that I have successfully gotten the Dialgizmo to work - dial-hold features and all on a Western Electric 302 phone by moving the dial shunt to the R instead of L1. I can access the dial-hold features by holding the dial for three to four full seconds, not two, which is not useful when dialing to some electronic systems. So..I will be moving on to install the Rotatone unit and will compare them on a separate subject that I have started on another forum subject. If anyone wants a summary of how to get the Dialgizmo to work properly on the WE 302, please email me, otherwise this is closed. Thanks again to all who posted here, it provided me some reference while I reviewed the problems with my phone and I learned much.