Compaq Contec COM-2(PC)F - Manual (Page 43)

System Reference
COM-2(PC)F
34
Circuitry Diagrams
TXD, RTS, DTR
RXD, CTS, DSR
SN75188
SN75189
15pF
Figure 4.1. Circuitry Diagrams
Block Diagram
The following is a block diagram of the COM-2(PC)F interface
board.
ADDRESS
DECODER
DATA
BUFFER
Data Bus
(D7~D0)
IB
M
-P
C
/A
T
B
U
S
CNTROL
BUFFER
Addr. Bus
(A9~A3)
AEN
Addr. Bus
(A2~A0)
IOR
IOW
RESET
NS16550
CLOCK
COM-2(PC)F
CN1
Serial Port
CN2
Serial Port
NS16550
RS-232C
DRIVER &
RECEIVER
RS-232C
DRIVER &
RECEIVER
INTERRUPT
JUMPER
INTERRUPT
VECTOR
REGISTER
IRQ3~7,
IRQ9~12,
IRQ14, 15
Figure 4.2. COM-2(PC)F Block Diagram