Contec COM-2DL-PCI, Руководство пользователя, Страница: 22 / 62

2. Setup
COM-2PD(PCI)H, COM-4PD(PCI)H
15
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 100
Ω
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 100
Ω
, set the terminator switch OFF and insert an external
terminator.
Table 2.2. Setting of Terminator
SW2,
SW4,
SW6,
SW8
Not inserted
1
3
2 4
ON
RTS
TxD
CTS
RxD
Factory
setting
- Half-duplex
Terminator
(Bit 3)
(A) (D) (C) (B)
1
3
2 4
ON
RTS
TxD
CTS
RxD
[B or C]
SW2,
SW4,
SW6,
SW8
1
3
2 4
ON
RTS
TxD
CTS
RxD
1
3
2 4
ON
RTS
TxD
CTS
RxD
Insert the
terminator
[A or D]
SW2,
SW4,
SW6,
SW8
Terminator
(Bit 3)
Not insert the
terminator
Not insert the
terminator
Figure 2.4. Party Line Connection