Dial Intercom PCB card

[WesternElectricBen]

Here's the fun part: the buttons---these came in at least 3 sizes: 1 button, 4 button and 8 button.

http://www.ebay.com/itm/310704841341

There was a phone man here in Atlanta named Red Hooks that all the other techs had to go behind after he had worked on these at City Hall. He would always screw up the wiring. His standard line was, "What you have here is raw batt'ry [sic]."

I never knew that made buttons in clusters like that, I've only seen them in a singular part connected off the side of the phone.

Ben

[WesternElectricBen]

Hey Ben, notice which two pins are missing on the 400D card: 3 and 18. That's because they are  the input for A Battery (filtered 24 Volts DC) for the intercom.

Weird, whats a battery have to do with this?

[AE_Collector]

All the manual intercom does is supply Talk battery through an inductor so that the same power supply can provide multiple talk paths without it being a big party line.

Terry

[WesternElectricBen]

All the manual intercom does is supply Talk battery through an inductor so that the same power supply can provide multiple talk paths without it being a big party line.

Terry

Ah ok, thank you. So the dial intercom cards are no good?

Ben

[poplar1]

Hey Ben, notice which two pins are missing on the 400D card: 3 and 18. That's because they are  the input for A Battery (filtered 24 Volts DC) for the intercom.

Weird, whats a battery have to do with this?

Even though the electricity source is a power supply, it's still called "Battery."

Did you know that in the central office there *are* real wet-cell batteries? They are charged from commercial power, and if commercial power is interrupted, there is a generator about the size of a school bus that they can crank up to keep the batteries charged. Central offices now operate on 48 VDC; older COs and many PBXs run on 24 VDC.

Look at your power supply. The outputs are 10 VAC,  18VAC,  24VDC B Battery) and 24VDC A Battery.

10 Volts AC is used for the lamps and (10V) buzzers and the interrupter(?)*
24 Volts DC UNFILTERED (B Battery) operates the relays on the KTUs
24 Volts DC FILTERED (A Battery) is used only for intercom.
You don't want unfiltered DC to try to talk on, because it will make it difficult to hear over the ripple noise.

*OK, I can't remember now whether the interrupter uses 10VAC or 24VDC.

[WesternElectricBen]

Hey Ben, notice which two pins are missing on the 400D card: 3 and 18. That's because they are  the input for A Battery (filtered 24 Volts DC) for the intercom.

Weird, whats a battery have to do with this?

Even though the electricity source is a power supply, it's still called "Battery."

Did you know that in the central office there *are* real wet-cell batteries? They are charged from commercial power, and if commercial power is interrupted, there is a generator about the size of a school bus that they can crank up to keep the batteries charged. Central offices now operate on 48 VDC; older COs and many PBXs run on 24 VDC.

Look at your power supply. The outputs are 10 VAC,  18VAC,  24VDC B Battery) and 24VDC A Battery.

10 Volts AC is used for the lamps and (10V) buzzers and the interrupter(?)*
24 Volts DC UNFILTERED (B Battery) operates the relays on the KTUs
24 Volts DC FILTERED (A Battery) is used only for intercom.
You don't want unfiltered DC to try to talk on, because it will make it difficult to hear over the ripple noise.

*OK, I can't remember now whether the interrupter uses 10VAC or 24VDC.

Oh, I see, that is interesting. The generator must be a gas guzzler! Thanks for the info.

Ben

[poplar1]

All the manual intercom does is supply Talk battery through an inductor so that the same power supply can provide multiple talk paths without it being a big party line.

Terry

Ah ok, thank you. So the dial intercom cards are no good?

Ben

The only thing that is "no good" are the ITT cards that Phil mentioned yesterday.

You said you wanted a card that would fit in the shoebox (551) KSU. While a 401A card will do that, you won't be able to dial a number to "buzz" another station. Instead, you have buttons to push. The 401A card is "good," just not dial selective.

One other possibility is the RT-1900 as previously discussed. This, too, is "good," but it won't fit in a 4" slot in the shoebox.

[WesternElectricBen]

All the manual intercom does is supply Talk battery through an inductor so that the same power supply can provide multiple talk paths without it being a big party line.

Terry

Ah ok, thank you. So the dial intercom cards are no good?

Ben

The only thing that is "no good" are the ITT cards that Phil mentioned yesterday.

You said you wanted a card that would fit in the shoebox (551) KSU. While a 401A card will do that, you won't be able to dial a number to "buzz" another station. Instead, you have buttons to push. The 401A card is "good," just not dial selective.

One other possibility is the RT-1900 as previously discussed. This, too, is "good," but it won't fit in a 4" slot in the shoebox.

Ok, I think I will go with the external. I like the fact of being able to dial.

Thanks,
Ben

[AE_Collector]

David: I am almost certain that the 1A2 interupter motors are 10VAC.

Ben: keep in mind now that an outboard Dial intercom is great on a key on a 1A2 key phone and will work on a single line phone too but the ringer has to be a 10 VAC buzzer on a seperate pair to the phone. Also keep in mind that you could use stations from a Panasonic PBX on keys on 1A2 phones. That would be better if you want to use some single line phones as the Pana will ring the bells in the phones but you would need 90VAC buzzers in the keysets or the ringer found in some keysets

[WesternElectricBen]

David: I am almost certain that the 1A2 interupter motors are 10VAC.

Ben: keep in mind now that an outboard Dial intercom is great on a key on a 1A2 key phone and will work on a single line phone too but the ringer has to be a 10 VAC buzzer on a seperate pair to the phone. Also keep in mind that you could use stations from a Panasonic PBX on keys on 1A2 phones. That would be better if you want to use some single line phones as the Pana will ring the bells in the phones but you would need 90VAC buzzers in the keysets or the ringer found in some keysets

Am I right, so what your saying is that I would need to add a buzzer?

[poplar1]

David: I am almost certain that the 1A2 interupter motors are 10VAC.

Ben: keep in mind now that an outboard Dial intercom is great on a key on a 1A2 key phone and will work on a single line phone too but the ringer has to be a 10 VAC buzzer on a seperate pair to the phone. Also keep in mind that you could use stations from a Panasonic PBX on keys on 1A2 phones. That would be better if you want to use some single line phones as the Pana will ring the bells in the phones but you would need 90VAC buzzers in the keysets or the ringer found in some keysets

Am I right, so what your saying is that I would need to add a buzzer?

Do you have a 118a Ringing Generator with your shoebox?

[WesternElectricBen]

David: I am almost certain that the 1A2 interupter motors are 10VAC.

Ben: keep in mind now that an outboard Dial intercom is great on a key on a 1A2 key phone and will work on a single line phone too but the ringer has to be a 10 VAC buzzer on a seperate pair to the phone. Also keep in mind that you could use stations from a Panasonic PBX on keys on 1A2 phones. That would be better if you want to use some single line phones as the Pana will ring the bells in the phones but you would need 90VAC buzzers in the keysets or the ringer found in some keysets

Am I right, so what your saying is that I would need to add a buzzer?

Do you have a 118a Ringing Generator with your shoebox?

What does that look like?

[AE_Collector]

Yes, each intercom station has the common T+R plus an individual pair for a buzzer. Coming out of the dial intercom box is the common T+R plus a whole bunch of buzzer pairs identified as each station number.

If you have a 90VAC ringing source with your shoebox you may be able to do 90 volt ringing but still on seperate pairs from the T+R.

Terry

[WesternElectricBen]

Yes, each intercom station has the common T+R plus an individual pair for a buzzer. Coming out of the dial intercom box is the common T+R plus a whole bunch of buzzer pairs identified as each station number.

If you have a 90VAC ringing source with your shoebox you may be able to do 90 volt ringing but still on seperate pairs from the T+R.

Terry

Uh, okay..

I'l keep that in mind.

Ben

[poplar1]

David: I am almost certain that the 1A2 interupter motors are 10VAC.

Ben: keep in mind now that an outboard Dial intercom is great on a key on a 1A2 key phone and will work on a single line phone too but the ringer has to be a 10 VAC buzzer on a seperate pair to the phone. Also keep in mind that you could use stations from a Panasonic PBX on keys on 1A2 phones. That would be better if you want to use some single line phones as the Pana will ring the bells in the phones but you would need 90VAC buzzers in the keysets or the ringer found in some keysets

Am I right, so what your saying is that I would need to add a buzzer?

Do you have a 118a Ringing Generator with your shoebox?

What does that look like?

http://www.classicrotaryphones.com/forum/index.php?topic=7026.msg79858#msg79858

SEE REPLY #11 For picture