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Chapter 3: Installation
NOTES (continued):
2. When configured as DCE, Data Terminal Ready and Request to Send signals
may be used to disable the line driver (see S3). The remote unit will sense this
condition and its Data Carrier Detect signal will become negative.
3. When configured as DTE, Data Terminal Ready will be active when the remote
unit is driving the line.
4. When configured as DTE, Data Carrier Detect and Clear to Send signals may be
used to disable the line driver (see S3). The remote unit will sense this condition
and its Data Terminal Ready signal will become inactive.
Switches
S1 2-position slide switch (DTE/DCE)
S2 2-position push button switch (loopback); Push button will be in “out”
position for loopback.
S3 4-position DIP switch (option switches)
Table 3-4. S1 switch.
Position
Function (See description of RS-232 DB9 connector)
A
Configure as DCE for connection to PC serial port
B
Configure as DTE to simulate PC serial port output
Table 3-5. S2 switch.
Position
Function (See Figure 3-2)
OUT
Normal operation
IN
Loopback
NOTE: When switch S2 is in the loopback position, the output of the local unit is
fed back to its input, and the line is looped back so the remote unit can
test the line integrity. The remote unit will actually see twice the distance
of the line. This should be taken into consideration when determining the
maximum baud rate at which the loopback test will be successful.
The local loopback path is compensated for zero length cable.
