AT&T System 85 - Manual (Page 139)

CHAPTER 9. GLOSSARY
T r u n k
A communications channel between two switching systems.
Trunk Group
Telecommunications channels assigned as a group for certain functions.
Turnkey
A button turned clockwise or counterclockwise on a backup telephone/voice terminal (used
with Centralized Attendant Service [CAS] at a branch location) switches between on-hook
and off-hook status. When pressed, the button flashes the switchhook.
Vector Directory Number (VDN)
An extension number that is assigned an internal extension number (but not assigned to an
equipment location).
Voice Terminal
Identifies all digital and hybrid model telephones.
Wide Area Telecommunications Service (WATS) Trunk
A telecommunications channel used for special direct distance dialing.
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