Mitel 470 System Manual page 134

Installation
Power supply critical xy m
prox.150 m).
System phones MiVoice 5361, MiVoice 5370 and MiVoice 5380 only:
During start-up, these system phones carry out a detailed measurement of the availa-
ble power. A warning is shown on the display if the result is inadequate:
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 accordingly.
– The backlighting of the MiVoice 5380 display is brighter if the phone is powered by a power
supply unit.
Rating examples
Example 1:
MiVoice 5370
Maximum power requirements as per Tab. 60: 1220 mW
Fig. 47 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 MiVoice 5380 with 2 MiVoice M530 expansion key modules
Power requirements as per Tab. 60: 1340 + 300 + 300 = 1940 mW.
Fig. 47 indicates:
• Maximum line length for a wire diameter of 0,4 mm: 520 m
• Maximum line length for a wire diameter of 0,5 mm: 820 m
• Maximum line length for a wire diameter of 0,6 mm: 1170 m
Example 3:
Evaluation of an existing line installation
Line diameter: 0.5 mm
Loop resistance: 120 Ω
Fig. 47 indicates:
• Line length: 660 m
• Power available: 2120 mW
134
is generated on the phones connected last (accuracy ap-
Line power too
Mitel 470 as of R4.1
syd-0585/1.2 – R4.1 – 08.2016