Quote:
Originally Posted by dagskarlsen
'...and pretty often on European telephones something disconnecting the ringer when going off hook is pretty common.'
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I've just dug out the circuit-diagram for my 1968 Ericsson Dialog (model No: 115.139) and the gravity switch is indeed configured like that.
There are two sets of contacts: one N/C and one C/O set. The bell capacitor sits before the changeover contact, and when the handset is on rest, the line A is routed via the N/C contact of the C/O set to the bell and back to the line B.
When the handset is lifted, the N/O contact of the C/O set closes, switching the bell capacitor into series with a resistor (spark-quencher) across the dial pulse contacts, and the N/C contact opens, disconnecting the bell from the line.
The other, N/C set of contacts is connected directly to the A line and switches in the mic and pulse contacts.