Bell Set 64D connection to hub? - UK Vintage Radio Repair and Restoration Discussion Forum

Evan47487 · 4th Mar 2024, 6:52 pm

Hello, can anyone help with what connections I need to connect the bells to the BT hub, I've removed the centre link in an attempt to get them to ring. Do I need to add a 3k3 resistor anywhere as with other bells? I've attached a pic of the bells. Tia.

Dave Moll · 4th Mar 2024, 7:46 pm

Without the centre link, they will be open-circuit. If you feel the need for a resistor, you can place it instead of the link. You will, however, need a 1.8µF (or thereabouts) in series with the bell coils, either by placing it within the bell enclosure and connecting the combination across the A and B legs of the line, or if using an external capacitor such as in an ADSL filter, between the A leg and the ring wire.

edit: I should add that the above assumes your hub has a telephone socket.

Evan47487 · 4th Mar 2024, 8:14 pm

Thanks so much Dave, extremely helpful. I'll get onto this soon.

Dave Moll · 4th Mar 2024, 10:05 pm

By the way, the forum appears to have changed my mu (in microfarad) to a question mark.

Station X · 4th Mar 2024, 10:19 pm

Alt+230'd

Dave Moll · 5th Mar 2024, 9:10 am

Thanks for that. I'm just puzzled why my "µ" (from character map) didn't remain as one. I'll use the ALT+number approach in future!

Station X · 5th Mar 2024, 10:38 am

I initially tried pasting one in from elsewhere, but it appeared as a question mark.

Back on topic please. there's a thread some where about how to type µ etc.

dagskarlsen · 5th Mar 2024, 7:43 pm

British Telecom used a master socket, and 3 wires in the house, one common, one line, and one ringer-line trough a 1.8 uF capacitor.
All the ringers were without capacitor. If one ringer had to high load compaired with the others it did "steal" too much of the energy. That might be compensated with series resistors (or capacitors). It is actually no easy way to calculate the right values, but 3k3 resistors are often used with an OK result.

4th Mar 2024, 6:52 pm	#1
Evan47487 Diode Join Date: Oct 2021 Location: Rhuddlan, Denbighshire, Wales. Posts: 7	Bell Set 64D connection to hub? Hello, can anyone help with what connections I need to connect the bells to the BT hub, I've removed the centre link in an attempt to get them to ring. Do I need to add a 3k3 resistor anywhere as with other bells? I've attached a pic of the bells. Tia. Attached Thumbnails

4th Mar 2024, 7:46 pm	#2
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,133	Re: Bell Set 64D connection to hub? Without the centre link, they will be open-circuit. If you feel the need for a resistor, you can place it instead of the link. You will, however, need a 1.8µF (or thereabouts) in series with the bell coils, either by placing it within the bell enclosure and connecting the combination across the A and B legs of the line, or if using an external capacitor such as in an ADSL filter, between the A leg and the ring wire. edit: I should add that the above assumes your hub has a telephone socket. __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

4th Mar 2024, 8:14 pm	#3
Evan47487 Diode Join Date: Oct 2021 Location: Rhuddlan, Denbighshire, Wales. Posts: 7	Re: Bell Set 64D connection to hub? Thanks so much Dave, extremely helpful. I'll get onto this soon.

4th Mar 2024, 10:05 pm	#4
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,133	Re: Bell Set 64D connection to hub? By the way, the forum appears to have changed my mu (in microfarad) to a question mark. __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

4th Mar 2024, 10:19 pm	#5
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Bell Set 64D connection to hub? Alt+230'd __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

5th Mar 2024, 9:10 am	#6
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,133	Re: Bell Set 64D connection to hub? Thanks for that. I'm just puzzled why my "µ" (from character map) didn't remain as one. I'll use the ALT+number approach in future! __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

5th Mar 2024, 10:38 am	#7
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Bell Set 64D connection to hub? I initially tried pasting one in from elsewhere, but it appeared as a question mark. Back on topic please. there's a thread some where about how to type µ etc. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

5th Mar 2024, 7:43 pm	#8
dagskarlsen Heptode Join Date: Jan 2008 Location: Hakadal, Norway Posts: 643	Re: Bell Set 64D connection to hub? British Telecom used a master socket, and 3 wires in the house, one common, one line, and one ringer-line trough a 1.8 uF capacitor. All the ringers were without capacitor. If one ringer had to high load compaired with the others it did "steal" too much of the energy. That might be compensated with series resistors (or capacitors). It is actually no easy way to calculate the right values, but 3k3 resistors are often used with an OK result.