User Interface
A user could select any available phone line simply by pressing the appropriate line button and picking up the handset. A caller could place a call "on hold" by pressing the red "hold" button. Doing so would also mechanically release the depressed line button, allowing the user to select another line.
An individual worker or executive might have a set with just a few lines "appearing." The system attendant (receptionist) might have a set with many lines appearing so that they could monitor the status of all incoming lines simultaneously.
These systems also supported manual buzzers, intercom lines (with or without selective ringing), music on hold, and other simple features. The features were provided on a line-by-line basis by the selection of particular Key Telephone Units (KTUs) plugged into a pre-wired backplane in the central control unit.
Optional components for the 1A2 could also provide a function called 'I-Hold,' where a call could only be retrieved off hold at the phone that originally placed the line in the hold mode. The cadence of the 'I-Hold' lamp signal was steady illumination punctuated by a series of rapid blinks (produced by a module called a 'flutter generator') every couple of seconds.
Read more about this topic: 1A2 Key System
Famous quotes containing the word user:
“A worker may be the hammer’s master, but the hammer still prevails. A tool knows exactly how it is meant to be handled, while the user of the tool can only have an approximate idea.”
—Milan Kundera (b. 1929)