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

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