Question: What voltage should be across the RS485 terminals from Touch Screen to Gateway
Answer: 0.1V to 1.2V DC (Intermittent or no communication)
1.2V to 3V DC (Possible communication delay)
3V to 5V DC (Good communication)
Question: What protocol is transmitted on the RS485 terminals on the Touch Screen
Answer: There are 2 options:
ORC-NET (orcomm protocol)
HC2-RS485 (Modbus)
Question: What is the purpose of the RS485 power on the Touch Screen
Answer: The +12V and GND are for extension alarm module (100mA)
Question: What is RS485 (A) and RS485 (B)
Answer: RS485 A is 485- (yellow wire)
RS485 B is 485+ (green wire)
Question: What is the difference between all of the (A) / (B) terminals on the Orcomm Gateway
Answer: ORCNET (A) (B) - this terminal allows propriety communication (120 ohm internal resistor)
IN (A) (B), OUT (A) (B) - these terminals are used for Modbus / RS485 through connection with no resistors.