GTE Automatic Electric Vintage Rotary Dial Telephone

Vintage black rotary dial desk telephone
GTE - Automatic Electric

Testing results from standard landline connected directly to a wall jack:
Calls can be made and received
Does not ring
There doesn't seem to be a volume control dial on the bottom, so I'm thinking this is a bedroom extension telephone. No sound so your sleep isn't distrubed.

Plastic dial rotates and returns smoothly
No cracks or chips in the housing

Note wire hookup
Handset has no markings
Cradle: Automatic Electric Northlake, Ill USA
Bottom: NB802 CXX 5-65-8
Back: AC-1