skipp025 posted:
I've got a 1000 ohm sounder here that I'd like to operate. Is/was there
as standard/defined voltage or current used by telegraph services for the
various mechanical telegraph sounders, based on their coil resistance?

Many sounders were intended for operation at about 20 mA. Others were for
puting into 62.5 mA circuits.

12V would be good enough for just playing around with it.

Don