American Fibertek MT-05B - Manual (Page 3)

3
This unit requires a 24 VAC power source with an isolated output for proper operation. Current draw is
approximately 2.5 VA maximum. In the USA and in Canada an American Fibertek PS-24 is supplied
with this unit. ANSI/NFPA 70 Class 2 wiring is recommended.
POWER CONNECTION
Power is supplied to the unit via a two pin terminal connector. See the drawing at the bottom of this
page for proper location of the 24 volt ac input.
FIBER CONNECTION
The fiber optic connection is made via a ST connector located on the side of the unit.
AUDIO INPUT LEVELS
The ideal audio input level is 0dBm
600
. (This is 1mW across the 600Ohm input impedance.) On a
voltage basis, this is equal to 0dBV or 2.19 Vp-p. Higher input levels will cause increased distortion. Up
to +3dBm, the distortion will increase a small amount. Above this level the distortion will increase
rapidly. Lower input signal levels will reduce the signal to noise ratio. In either balanced or unbalanced
input configuration, the input impedance is 600 Ohms.
BALANCED AUDIO INPUT CONNECTIONS
The audio input connections are made via a three pin terminal connector on the side of the unit. A
balanced audio input is directly connected to the plus and minus inputs. The shield or earth wire is
connected to the ground terminal. See the drawing below for proper orientation of the audio input wires.
For optimum performance the audio wires should be the shortest length practical.
UNBALANCED AUDIO INPUT CONNECTIONS
The audio input connections are made via a three pin terminal connector on the side of the unit. To
connect an unbalanced signal to the input, the audio signal is connected to the plus input. The shield or
ground wire is connected to both the minus and the ground terminals. When used in the unbalanced
configuration, there will be a loss of –6dB at the output of the corresponding fiber receiver. See the
drawing on the next page for proper orientation of the audio input wires. For optimum performance the
audio wires should be the shortest length practical.