I didn't mean that the user could ground it, just that the user shouldn't depend on being grounded. It may be grounded at the installer's discretion. You can't depend on it.
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13 years ago
Telephone Tip/Ring Question
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13 years ago
I'm sure he meant the universal 'you' as electronics don't care if the 'you' connecting things is wearing a Telco uniform or not.
The phone line is a balanced pair with neither side, ring or tip, wired to ground on the subscriber end and checking for shorts to ground (insulation failure, water ingress, etc) is one of the first faults they look for.
On the Telco end (or line card) the balanced pair is AC isolated from the DC supply (and ground) through coils (or equivalent) so there is a DC path but no AC path.
As Lesher noted, back in olden days subscriber party line ringers could be connected to ground but the thing that made the bell go ding-a-ling-a-ling was a (solenoid) coil so AC imbalance was minimized