Philips BDL3221V User manual - Page 89

3. Serial Interface Communication Protocol 3.1 General specifications 3.1.1 Protocol definition Communication to the main monitor microprocessor is possible through the serial port, which support a communication protocol dedicated to BDS only. The protocol is specifically designed to allow data communication in half duplex multi-point environments, but it can also be used for half duplex point-to-point RS-232 communication. 3.1.2 Communication characteristics A half duplex communication is implemented starting from the concept of a master-slave structure, where the monitor is supposed to be the slave. The first action is always taken by the master, which can be either a built-in PC-based video controller in a MASTER monitor or any external device (acting a server) interfaced to the monitor. After sending a command or a request in the appropriate format (see section 3.2), the master receives form the slave an acknowledgement, which tells the transmitter whether the command is not valid (or not executable, anyway) or it is accepted. In case of a request, the requested information is sent back and it becomes the acknowledgement by itself. If the poll sequence has been sent, the acknowledgement tells the transmitter the monitor status, i.e. whether it is ready or busy and other information. 3.1.3 RS232 pin assignment There is a 9-pin male connector on the set for RS232 communication. The pin assignment is as following table. Pin No. 1 2 3 4 5 6 7 8 9 Function GND RxD TxD NC GND NC NC NC NC Description Signal Ground Receive Data Transmit Data Not Connected Signal Ground Not Connected Not Connected Not Connected Not Connected 3.1.4 RS232 settings This section describes the parameters used during the whole communication process. Baud rate Data bits Parity Stop bit Flow Control 57600 bps 8 bits None 1 None Philips [ NAME ] 2838 100 05424 23 140 07