[asterisk-users] The plain old PBX functionality

[A J Stiles]

On Friday 08 Aug 2014, Gergo Csibra wrote:
> Hi,
> 
> back in the old analog telephony days there was "digital" PBX-es and
> digital "system" phonesets. This phonesets have had many individual
> illuminatable buttons connected with extensions. The PBX can show on
> the buttons if some extension is ringing (blinks) or busy (constant
> light), and the user can transfer the call with one touch (pressing
> one of this button).
> 
> I search this functionality in Asterisk. What versions, and what
> extension functions (or other settings), and what VoIP phones can do
> this?

What you are looking for is a "Busy Lamp Field"  (BLF).  This can usually be 
controlled by custom SIP headers  (though naturally, every manufacturer's 
implementation is ever so slightly different).

N.B.  Be sure to *avoid* Digium phones if you want BLF functionality!  Making 
use of this feature would require you to pollute your system by installing a 
toxic, binary-only module.

-- 
AJS

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