Octagon PC-600, Справочное руководство

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or DB–9 male (VTC–20M) connectors which plug directly into a 9–pin PC
serial cable.
Note When interfacing the PC–600 to your desktop PC, you must use a null
modem adapter.
Figure 5–2 VTC–20F and VTC–20M cables
P2
P1
P3
VTC-20F and VTC-20F Cables
COM Ports as RS–232 I/O
COM1, COM2, COM3 and COM4 are 8-wire RS–232 interfaces. You can
connect four serial devices. Note that COM3 and COM4 share IRQ9. You
must access the COM ports to determine which generated the interrupt.
In the default configuration, the Video jumper W12[5–6] is installed. This
jumper automatically disables the Serial Video option in the Advance
menu in Setup, and both COM ports are available for serial I/O devices.
In some instances, such as running a program on the PC–600 that will
ultimately be used on another card without on-board video, you might
want to remove the Video jumper and still use COM1 as a COM port
instead of a serial console. In this instance, you must go into Setup and
set Serial Video in the Advanced menu to Disabled.
COM3 and COM4 as RS–422 and RS–485 networks
COM3 and COM4 can be used as RS–422 or RS–485. RS–422 and RS–
485 use differential signaling to communicate between the devices on a
network. Differential signal reduces the effect of environmental noise,
allowing communication over distances up to 1200 meters.
RS–422 is a point-to-point configuration, RS–485 is a multi-node
configuration that allows up to 32 nodes on a network. COM3 and COM4
can be configured as either RS–232, RS–422, or RS–485. Refer to Tables
5–1 and 5–3.
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