4
RS-232 TO FIBER OPTIC MULTIPLEXOR
5. The fifth mode is synchronous with external clocking (the terminal
device supplies the clock to the multiplexor). Like all other modes but the
third, this mode supports DTR/CTS handshaking. The mux will accept and
adapt to any externally-clocked data rate up to 14,400 bps. This is identical to
Mode 2, with the exception that the auxiliary signal is clock timing from the
DTE (terminal device).
The multiplexor is housed in a metal enclosure. The case has rubber feet
for stand-alone use on a table top or shelf, but can also be rack-mounted in
a standard 19-inch rack by attaching the optional rackmounting brackets
(product code RM901).
2.2 Physical Description
This section describes the physical characteristics of the multiplexor.
The front panel (see Figure 2-1, below) of the mux has no controls, but
has two LED indicators in the lower right-hand corner. The red LED at the
extreme right is the POWER ON indicator. The green LED to its left, labeled
“SDCD” (System Data Carrier Detect), indicates that an optical signal is being
received. It does not indicate that the signal is error-free or that the
multiplexor is in synchronization with the incoming signal. If the optical-
receiver connector (RX) is disconnected and open, it is possible that external
light sources could trigger the optical receiver and cause this LED to light.
The components on the rear panel of the multiplexor are shown in
Figure 2-2 on the next page, which illustrates a 16-channel unit. The rear
panel of the 8-channel mux is the same, except that a plate covers the holes
for the connectors and switches of channels 9 through 16.
1. Optical-Transmitter Connector: SMA or ST compatible connector for the
optical transmitter.
Figure 2-1. The front panel.
SDCD
POWER
