12
RS-232 TO FIBER OPTIC MULTIPLEXOR
Signals fed into the A connector at one end of the system (attached to a
terminal device connected to one mux) will be received at the A connector at
the other end of the system (attached to a terminal device connected to the
other mux), and vice versa. The B and C connectors work the same way. The
numbers on each connector are the pin numbers on the mux channel’s
connector through which the signals actually pass. For more detailed
information, see
Section 4.3.3
.
To set a given channel for this mode, set that channel’s STD switch position
ON, all others OFF.
NOTE
Data coming into the mux from the B device on Pin 14 will be present on
Pin 15 of the mux’s input connector. See
Section 4.1.5
for the reason why.
4.1.4 S
YNCHRONOUS
D
ATA
L
INE WITH
I
NTERNAL
C
LOCK
(M
ODE
4)
For a channel in this mode of operation, the local multiplexor supplies the
transmit clock to its attached terminal device on Pin 15 and transmits the
same clock, with the terminal device’s synchronous transmit data, to the
remote multiplexor. The remote mux (which can be set for either internal
or external clocking) will output the clock signal from the local mux on
Pin 17 of the corresponding channel’s connector.
Data Terminal Ready controls Clear to Send the same way it does in Modes
1 and 2. Available internal-clock data rates are 1200, 2400, 4800, 9600, and
19,200 bps.
To set a given channel for this mode, set the position of that channel’s DIP
switch that corresponds to the desired data rate (see Figure 4-1 on the next
page) ON, and all other positions OFF. A channel will not operate properly
with two data rates selected, and any other channel that has either of those
data rates selected will also malfunction.
4.1.5 S
YNCHRONOUS
D
ATA
L
INE WITH
E
XTERNAL
C
LOCK
(M
ODE
5)
For a channel in this mode, the local multiplexor receives the transmit clock
from its attached terminal device on Pin 14 and passes it on to the remote
multiplexor. The remote mux (which can be set for either internal or
external clocking) will output the clock signal from the local mux on Pin 17
of the corresponding channel’s connector. (This mode is essentially the same
as Mode 2: clocking is carried by the auxiliary signal instead of data or
another type of control.)
