Samsung SRP-350PG - SRP 350 B/W Direct Thermal Printer Service Manual page 89

9 Troubleshooting
9-8 RS-485 Serial Communication Problem
RS-485 Problem
Communication
Failure?
H/W
Handshake
End
9-8
Y
N
1. Check the connection of the RS-485 Connector and Other side
2. Check the I/F Cable whether it is open or short
3. Check the Txd, Rxd Pin on CPU
4. Check the MAX488 Driving Chip and reated Circuit
on I/F PBA
5. Check whether Signal is affected by the Cable Noise
N
Y
1. Check the connection of the H/W
handshaking Line and Other side(DR1,2/CS1,2)
2. Check the I/F Cable whether it is open or short
3. Confirm the H/W handshaking Protocol
4. Check the Voltage Level of each Line
Samsung Electro-Mechanics