Nortel Meridian M3900, Reference Manual

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128 Environmental, power, and safety considerations
555-4001-136 Standard 05.06 May 2002
Power consumption
Table 31 shows the power consumption for the M3900 series sets.
Line engineering
M3900 Series Meridian Digital Telephones use twisted pair wiring on
transmission lines. The maximum acceptable loop length is 1067 m.
(3500 ft.), assuming 24 AWG (0.5 mm) standard twisted wire with no
bridge taps. A 15.5 vdB loss at 256 kHz defines the loop length limit.
Longer lengths are possible, depending on the wire’s gauge and
insulation.
Table 31
M3900 sets power consumption
M3901 M3902 M3903 M3904 M3905
Idle 29.3 37.3 42.5 31.5 15.02
H/F Nominal 45.7 48.7 37.5
H/F Maximum 64.3 59.7 46.4
DBA Idle 39.29 15.31
DBA H/F Nominal 45.9
DBA H/F
Maximum 52
2 KBA Idle 33.42 14.98
Note: Units of measurement are milli-amps (ma).
The M3905 uses a switch mode power supply and the M3904 uses a linear power supply.
When a handset is offhook with maximum volume, the current increases 2 to 5 ma using linear power
supply and 1.5 ma on the M3905 using switch mode power supply.
WARNING
Use only the line cord provided with the telephone. A line cord
designed for another telephone can cause damage to the
equipment.
Warning