off-hook

(redirected from Off hook)
Also found in: Acronyms.

off-hook

[′ȯf ‚hu̇k]
(communications)
The active state (closed loop) of a subscriber or PBX user loop.

off-hook

The state of a telephone line that allows dialing and transmission but prohibits incoming calls from being answered. The phone is off-hook when the handset is lifted off the base of a stationary phone or when Talk is pressed on a portable phone.

The term stems from the days when the handset rested on an actual hook. When it was removed, a spring caused contacts to press together, closing the circuit from the telephone to the switchboard in the central office (CO). When a handset is placed back on the base, it is said to be "on-hook," and the phone can receive a call. See central office.


There Really Was a Hook
The hook on this Kellogg telephone (circa 1899) was attached to a spring. When the handset was removed, the contacts inside completed the circuit between the telephone and the central office.
References in periodicals archive ?
Here's the issue: Because off-hook agents maintain an open SIP stream to particular gateways, in a multi-gateway deployment you need to understand how a call received on one gateway can be routed to an agent connected off hook to another gateway.
STRICKEN 3 Coral Strand ran aground off Hook Head, Co Wexford, yesterday
The Rising Sun sank off Hook Head claiming skipper Pat Colfer and Jimmy Meyler.
Page Zones allows a user to go off hook and broadcast a message to a select group of extensions through the telephone speakerphones.
Simon Mensing 5 Let off hook by Cerny after conceding second-half penalty with rash challenge.
Two men died when the Kilmore Quay based trawler, the Maggie B, sank off Hook Head on March 30, 2006.
Taco Bell(R) phone lines ring off hook and Web site nearly crashes
Giant humpback whales have been filmed breaching the surface three miles off Hook Head, Co Wexford, providing some of the most dramatic footage shot on our coastline.
The devices provide the complete interface between a switching system and a subscriber loop, and are equipped with battery feed and ringing feed to the line, two-wire to four-wire hybrid interfacing, and off hook and dial pulse detection.
He said he had heard Ger offering help to the search for the Pere Charles, which sank off Hook Head in Co Wexford just hours earlier but Ger was "told he was OK".