atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems A & K network terminal designations

I don't think I was making much sense last night! It's the charging and discharging of the coil which moves the bell hammer back and forth. The coil is already discharged by the time the AC signal is over. Don't know what I was thinking!

The ringer isolation capacitor is generally .47mfd at 200Vdc, non polarized. Remember that the ringing signal itself is 75-130 vac. Supposed to be 90vac, but this is where reality strikes. . Point being a 48-50 VDC capacitor would 'punch-through' and 'trip the ring' in the middle of the 1st ring cycle. At that point it might,or might not, 'heal' without removing the DC battery. OR, it might just explode and leave little pieces of capacitor scattered around and 2 wires 'waving in the breeze'. John C.

Without that capacitor, a direct connection instead, I recall you could sometimes hear the bell slightly tapping along with the digits when dialed from a rotary phone. Same when going off/on hook. I know so many are cancelling their landlines in their homes. I just can't bring myself to do it. Then my 1A2 system would only have an intercom line. I still prefer using my 2565 set over my cell phone any time I can. I was considering one of those "Magic Jacks" that supposedly provides free long distance with a one time fee, and connecting it to where line 2 used to be. I wonder how good the audio would be with that device.

If you do go with "Magic Jack" or similar, be aware that some of the earlier models of the 1A2 line cards don't play nice with anything but a true POTS line.

That's what I was wondering, if there was enough current and voltage for a 400E. You're going to get just so much out of a USB port. What I could do is make my own "talk battery" circuit with transformers and other components from a Rolm 8000 line card. I used the "A" battery from the KSU power supply. That's how I made the dial 9 circuits to get the CO line on the intercom only phones. I read a few reviews about the Magic Jack, some were very negative but about 50% were good.

I've got an M/J and it's ok. That said, I would not give up my POTS period! Which line will still be working 24 hours into an area wide power failure. (Ice storm, for instance.) M/J REQUIRES an operational USB port and DSL or Cable Broadband or it don' do nuttin'. Cable phone requires local power and working cable.
For $20/year, it's worth it for free L/D and secondary phone line. Sometimes it takes 2-3 tries to get a good connection, but what da ya want for $20/year!

I absolutely would keep my POTS. I've seen the cable co. package with TV, Internet & phone but wonder how long that battery would last during a power failure. Yep for only $20/year I wouldn't mind having to redial at times.

Surprisingly MagicJack works like a charm. The only trouble is 1 out of 3 store bought phones behind 5 line keyfields can't break dial tone. This may because the circuit it's connected to providing A lead control has a relay in series (From a 400E card) with the tip side. Maybe there's not enough current. It's kind of a backwards hold circuit, I converted line 5 to a
momentary push button which activates a relay for a few seconds. That interrupts A lead like a hold key would, allowing the phone to go on hook. I was surprised to see the MagicJack line still had enough current to take it back off hold. The 400E originally had the hold resistor replaced by one with a higher value to allow enough current to activate the relay and take it off hold, but low enough to still hold the line.

MagicJack's audio quality is very good, the receive level is higher than my telco line, sounds line a -5 line or better. There is a very slight clip from time to time, but not bad. There's a slight hum as I expect it's designed to plug into just one phone. I should try making a call when downloading music or 2 of the Xboxs are online.

Audio quality is definitely affected if there's alot of activity going on. It gets to be very choppy. I ended up making a circuit with an isolation transformer using A battey from the KSU power supply. Now all phones can dial out. The voltage directly from the MJ was just a little too low for one phone.