2. Introduction
The Fiber Optic Network Access Control A/B Switch is a
non-latching full-duplex optical switch. It is used to provide access to two different networks at the user’s
discretion.
The A/B Switch operates with a unique switching mechanism. When you connect (short) Pin 1 to Pin 2 on
the terminal block located on the back of the unit, the internal optical mirror mechanism will provide a
connection path between the Common port and port B. The front panel B LED will illuminate to indicate
that the connection path is B. If power is lost, or if the Pin 1 to Pin 2 connection on the terminal block is
removed, the Fiber Optic Network Access Control A/B Switch will revert to the Common port to port A
connection state.
The slide switch on the front panel operates in parallel with the rear panel terminal block contacts. When
the slide switch is in the ON position, the internal optical mirror mechanism will provide a connection path
between the Common port and port B, and the front panel B LED will illuminate to indicate that the
connection path is B. When in the ON position, the slide switch also provides a connection between pins 1
and 2 on the terminal block. This feature could be used to activate a set of remote contacts on a secondary
device.
The terminal block on the rear of the unit also provides 3 signal pins for remote status indication to allow a
programmable controller or similar device to determine the status of connection path through the Fiber
Optic Network Access Control A/B Switch (see table 3.1).
3. Installation
Place the switch in a location relatively free from vibration and mechanical disturbances.
Connect your fiber optic cables to the Common port, Port A and Port B. Note that the switch supports
separate transmit and receive paths, so you must be consistent when connecting the fiber pairs to the
switch.
Connect your remote contact across Pins 1 & 2 on the terminal block. If using a remote status indicator,
connect the remote status indicator to the terminal block (refer to table 3.1 for terminal block pin
assignment).
Note:
The external remote control circuit including cable and external dry contact closure cannot exceed
100 ohms resistance.
Apply power to the Fiber Optic Network Access Control A/B Switch using the 12 VDC power supply
provided. Either the A LED or the B LED should illuminate to indicate that the unit is energized and to
show the current connection state.
Pin 1
Active Contact
(to switch to port B)
Pin 2
Ground
Pin 3
Not Used
Pin 4
Status Relay N.C.
Pin 5
Status Relay COM
Pin 6
Status Relay N.O.
Table 3.1 - Terminal Block (Pin 1 is on the Left)
NOTE: Pin 4 & 5 are connected when in the Common Port to A Port connection state, Pins 5 & 6 are
connected when in the Common Port to B Port connection state.
1U Rackmount, Single
FONAC A/B Switch, with SC connectors
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