What does POTS stand for?

What does POTS mean?

POTS	Plain Old Telephone Service Governmental » Military
POTS	Plain Old Telephone Service Computing » Telecom
POTS	Plain Old Telephone Service Computing » Networking
POTS	Plain Old Telephone Service Computing » Drivers
POTS	Plain Old Telephone Service Computing » Hardware
POTS	Postural Orthostatic Tachycardia Syndrome Medical » Physiology
POTS	Postural Orthostatic Tachycardia Syndrome Medical » Hospitals
POTS	Plain Old Telephone Set Business » General
POTS	Purchasing On-line Tracking System Business » General
POTS	Parents Over The Shoulder Internet » Chat
POTS	Plain Old Telephone Service Governmental » US Government
PotS	Parting on the Square Internet » Chat
POTS	Poor Old Telephone System Miscellaneous » Funnies