Help wiring up field telephone

[PaulE]

Hi everyone.
I would like to know which is the best way to wire up two field telephones
A: connect the two wires direct to the terminals La to La and Lb/E to Lb/E
OR
B:Connect terminal La to La and earth the Lb/E terminals
If the latter is the best way do you earth/ground both telephones
Thanking you in advance for any help you can give me
Regards Paul

[reidmuller]

earthing them depends on the ground as it can be very weak so the best way to do it is to connect the two terminals