Samsung SRP-350PG - SRP 350 B/W Direct Thermal Printer Service Manual page 57

7 Special Circuit Descriptions
7-5 RS-485 Communication Block Diagram
CPU
M30624FGFP
TRANSMIT (PRI NTER)
DATA
SD1
SD2
RECEIVE (PRINTER)
RD1
RD2
7-6
TXD,RXD
DTR
CTS(Same as DSR)
Figure 7-9 RS-485 Communication Block Diagram
Transmission a data (1 Byte)
A-B = A-B =
(-)Level (+)Level
Received data (1 Byte)
Figure 7-10 RS-485 Waveform
TXD
RXD
DTR
CTS
A-B = A-B =
(-)Level (+)Level (-)Level
SD1
SD2
RD1
RD2
DR1
DR2
CS1
CS1
RS-485 I/F BOARD
"H"
"L"
(+)Level
Gnd
(+)Level
Gnd
Gnd
Gnd
A-B =
(+)Level (5V)
(+)Level (5V)
Samsung Electro-Mechanics