Radio Shack 26-1145 - Pin Serial Connector; Block Diagram

XTAL
CPU BUS
V
^i ii
yS
BRG
±_JL
RS-232-C
25
PIN SERIAL
CONNECTOR
UART
c
MODEM
STATUS
REGISTER
LEVEL
SHIFTERS
HANDSHAKE
LATCH
TTL
TO
EIA
LEVEL
SHIFTERS
^.
s.
EIA TO
TTL
^~
LEVEL
V
SHIFTERS
^_
+ 5
V IN
DC/DC
CONVERTER
1
VOLTAGE
DIVIDER
+12
V
OUT
—12
V
OUT
-5
VOUT
FIGURE 4.
RS-232-C BLOCK
DIAGRAM
11