Aastra OpenCom 100 Series Mounting And Commissioning User Manual page 205

Team Functions
Every call on a trunk key can be transferred to any other party by means of the R key.
For more information, refer to the chapter entitled "Consultation, Toggling, Transfer
and Conference" in the "Aastra 6771 / 6773 / 6775 (OpenPhone 7x)" user guide.
Line Busy Indication
If a line is busy, e.g. TrK 10 on Miller's telephone, the appropriate team key will indicate
this, e.g. TK 10 on Johnson's telephone.
Call Signalling
In this example, calls via trunk keys are signalled acoustically. Calls via team keys are
indicated by a visual signal (the team key LED flashes).
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