inward-outward dialing system

inward-outward dialing system

[¦in·wərd ¦au̇t‚wərd ′dī·liŋ ‚sis·təm]
(communications)
Dialing system whereby calls within the local exchange area may be dialed directly to and from base private branch exchange telephone stations without the assistance of the base private branch exchange operator; CENTREX, a service offered by some telephone companies, is a form of inward-outward dialing.