callback

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callback

(programming)
A scheme used in event-driven programs where the program registers a subroutine (a "callback handler") to handle a certain event. The program does not call the handler directly but when the event occurs, the run-time system calls the handler, usually passing it arguments to describe the event.

callback

(communications, security)
A user authentication scheme used by some computers running dial-up services. The user dials in to the computer and gives his user name and password. The computer then hangs up the connection and uses an auto-dial modem to call back to the user's registered telephone number. Thus, if an unauthorised person discovers a user's password, the callback will go, not to him, but to the owner of that login who will then know that his account is under attack.

However, some PABXs can be fooled into thinking that the caller has hung up by sending them a dial tone. When the computer tries to call out on the same line it is not actually dialing through to the authorised user but is still connected to the original caller.

callback

(communications)

callback

An authentication technique that calls the sender back. After connection is made, the receiving side breaks the connection and calls the sender to ensure that the logon was made from the authorized computer. Callback prevents a stolen ID and password from being used on a different machine. See also Web callback.
References in periodicals archive ?
Fonolo's own research has found that 63 percent of consumers prefer the option of a call-back over waiting on hold, and 75 percent say it is "highly appealing.
Beyond call-backs, it is also an ideal solution for small businesses to provide a cloud based customer support call centre.
In the case of certain basic computer system configurations, such as the terminal-to-central processing unit (CPU) link-up shown in Figure 1 or the CPU-to-CPU system in Figure 2, the call-back system can be programmed to recognize an authorized user by an identification code.
One4000 also offers a mobile call-back application and a PC/notebook call-back application.
The report identified a range of problems including staff shortages, difficulties in recruiting nurses and in the way calls were handled - most notably the call-back service It also criticised the lack of co-ordination between NHS 24 and other parts of the health service and the impact of changes to GPs' contracts relating to out-of-hours work.
SNP health spokeswoman Shona Robison said the figures raised questions over the decision to continue rolling out NHS 24 across Scotland She added: 'While the rise in complaints is worrying, the increase in call-back times is of even greater concern and exposes the Executive's staggering incompetence in managing the service.