Aastra 470, Системное руководство, Страница: 115 / 250

Installation
115
Aastra 470 as of R1.2
syd-0337/1.2 – R1.2 – 11.2011
Automatic detection of critical power supply situations
Only Aastra 5360, and phones of the Office series:
When a system phone (or a second such phone) is connected to the DSI bus, the
maximum power input is automatically determined; all the system phones (incl. ex-
pansion key module and alphanumerical keyboard) connected to the interface are
taken into account. The maximum power available is also determined based on the
calculated line length (assumption: Diameter = 0.5 mm). If the calculated power
available is below the maximum possible power input of the connected system
phones, the message "
Power supply critical xy " is generated on the phones con-
nected last (accuracy approx. 150 m).
System phones Aastra 5361, Aastra 5370 and Aastra 5380 only:
During startup, these system phones carry out a detailed measurement of the
available power. A warning is shown on the display if the result is inadequate:
Line
power too weak: External power supply required!
Notes
– Depending on the power available based on the line length on the
DSI-AD2 bus the ringing and hands-free volume decreases accord-
ingly.
– The backlighting of the Aastra 5380 display is brighter if the phone is
powered by a power supply unit.
Rating examples
Example 1:
Aastra 5370
Maximal power requirements as per
Tab. 56, page 112 : 1220 mW
Fig. 47, page 113 indicates:
• Maximum line length for a wire diameter of 0.4 mm: 840 m
• Maximum line length for a wire diameter of 0.5 mm: 1200 m
• Maximum line length for a wire diameter of 0,6 mm: 1200 m
Example 2:
An Aastra 5380 with 2 Aastra M530 expansion key modules
Power requirements as per
Tab. 56, page 112 : 1340 + 300 + 300 = 1940 mW.
Fig. 47, page 113 indicates:
• Maximum line length for a wire diameter of 0.4 mm: 520 m