Setting Of Terminator - Contec COM-2PD(PCI)H User Manual

Setting of Terminator

The terminator setting switch controls whether or not a terminator is inserted into each signal line. Set
the terminators on or off in accordance with the devices with which you are communicating. The
terminators on the board are 100Ω resistors. See Figure 2.4 for details on how to use terminators in a
multi-drop (party line) connection.
SW2 sets the terminator for channel 1, SW4 for channel 2, SW6 for channel 3 and SW8 for channel 4.
Each bit in the switch corresponds to a different signal line: bit 1 for RxD, bit 2 for CTS, bit 3 for TxD,
and bit 4 for RTS.
Setting Procedure
If you wish to use a terminator of other than 100Ω, set the terminator switch OFF and insert an external
terminator.
Table 2.2. Setting of Terminator
Not inserted
RTS
SW2,
TxD
SW4,
SW6,
CTS
SW8
RxD
- Half-duplex
Terminator
(Bit 3)
(A) (B)
Figure 2.4. Party Line Connection
COM-2PD(PCI)H, COM-4PD(PCI)H
Factory
setting
Terminator
(Bit 3)
(C) (D)
[A or D]
Insert the
terminator
RTS
SW2,
SW4,
TxD
SW6,
CTS
SW8
RxD
[B or C]
Not insert the
terminator
RTS
SW2,
TxD
SW4,
SW6,
CTS
SW8
RxD
2. Setup
Not insert the
terminator
RTS
TxD
CTS
RxD
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