User guide

5
Exchange Line
MF REN of 3
Extensions
MF REN of 4
(See notes below)
Dimensions
261mm long x 102mm wide x 63mm
deep (max)
Weight
1kg
Power Supply
220 - 240V AC 47-63 Hz
Plug Fuse Rating
3 Amp.
Power Consumption
16 watts maximum
Temperature
0 to 40°C working, -20 to +70°C
storage
Relative Humidity
0 to 95% (non-condensing)
TECHNICAL NOTES - cont’d
How many telephones can you connect?
This is important if you want to connect more than one piece of apparatus to
each extension. Each instrument (telephone, fax machine etc.) has a REN
(ringer equivalence number) value, which is usually written on it somewhere.
The total REN value of all instruments connected to an extension must not
be more than 4. If you have a BT telephone, you can assume that its REN
is 1 unless it is marked otherwise. If you connect telephones such that the
total REN value is more than 4 to one extension line, one or more of the
instruments will not ring and/or answer calls correctly.