Serial & Parallel Ports 10-5
Serial Port 2 (J7) RS485/RS422
If Serial Port 2 is configured for RS485 operation, it can support either full-duplex or
party line communication.
Full Duplex Operation (RS422):
Upon power-up or reset, the COM2 interface circuits
are automatically configured for full duplex operation. Pins 3 and 4 of J7 act as the
receiver lines and pins 5 and 6 act as the transmitter lines.
Party Line Operation (RS485):
In order to enable party line operation, the user must
first write "1" to bit 3 at I/O address 190H (or at 290H or 390H depending on W9
jumper). This allows the transceiver (pins 3 and 4 of J7) to be controlled by the RTS
signal. Upon power-up or reset, the transceiver is by default in "receiver mode" in
order to prevent unwanted perturbation on the line.
In party line operation, termination resistors R84 and R85 must be installed only on the
boards at both ends of the network.
The following table shows this connector's pin-out:
TABLE 10-3:
Serial Port 2 (J7) RS485/RS422 - Pin-Out
Pin
Number
Signal
Flow
Signal
Pin
Number
Signal
Flow
Signal
1
I
DCD
2
I
DSR
3
I/O
RXD(-)
4
I/O
RXD(+)
5
O
TXD(-)
6
I
TXD(+)
7
O
DTR
8
I
RI
9
-
GND
10
-
Not Used
Содержание PCI-993
Страница 31: ...Jumper Locations Configuration 2 7...
Страница 32: ...Jumper Locations Configuration 2 8 TABLE 2 1c Jumper Settings W13 W18 W22...
Страница 33: ...Jumper Locations Configuration 2 9 TABLE 2 1d Jumper Settings W24 W27 J14...
Страница 36: ...Connector Locations Pin Out 4 3 DIAGRAM 4 1 Connector Locations...
Страница 56: ...System 6 3 DIAGRAM 6 1 System Components Location Bottom of Board...
Страница 57: ...System 6 5 DIAGRAM 6 2 System Components Location Top of Board...
Страница 117: ...Video 13 2 DIAGRAM 13 1 Video Components Location Top of Board DIAGRAM 13 2 Video Components Location Bottom of Board...
Страница 127: ...PART THREE SOFTWARE REFERENCE 15 AMIBIOS SETUP 16 VIP UP SETUP 17 UPDATING BIOS WITH UBIOS 18 VT100 MODE...
Страница 172: ...VT100 Mode 18 3 DIAGRAM 18 1 VT100 Full Setup DIAGRAM 18 2 VT100 Partial Setup...
Страница 188: ...TEK933 Board Diagrams C 3 DIAGRAM C 1 TEK933 Assembly Top...
Страница 189: ...TEK933 Board Diagrams C 5 DIAGRAM C 2 TEK933 Assembly Bottom...
Страница 190: ...TEK933 Board Diagrams C 7 DIAGRAM C 3 TEK933 Configuration...
Страница 191: ...TEK933 Board Diagrams C 9 DIAGRAM C 4 TEK933 Mechanical Specifications...
Страница 197: ...Post Codes Error Codes E 2 to main BIOS in shadow RAM...