Serial Port Configuration

All BrightSign players offer serial I/O for diagnostic and interactive capabilities. Many models have a dedicated serial port (either DB9 or 3.5mm) to enable serial communication. This page outlines how to configure the player and host device for serial communication.

You can also view log output over the Diagnostic Web Server or Telnet/SSH, or enable the BrightScript debugger to debug BrightScript applications.

Signaling Settings

The following are the default serial settings for a BrightSign player. They can be changed in BrightAuthor or BrightScript.

• Baud rate: 115200

• Data: 8 bit

• Parity: none

• Stop: 1 bit

• Flow control: Hardware flow control is available on the 4Kx42, XDx32, and HDx22 (software flow control is not supported on any model).

Determining DTE/DCE

BrightSign players come in a variety of hardware configurations, including both Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE). Typically, BrightSign players are DCE devices; however, the following are DTE devices:

• 4Kx42

• XDx32

• HDx20

• HDx22

By default, DTE and DCE devices can only speak to their opposite. If the BrightSign player and the intended interface device are of the same type (both DTE or both DCE), a null-modem cable or converter can be used to transpose TX/RX signals to allow communication.

3.5mm Serial

The UART (asynchronous serial) interface is a 3.5mm (1/8") jack that uses RS-232 levels for communication^*. The receiver will tolerate input voltages between -30V and +30V, with anything below 3V interpreted as logical 1. The output signalling voltage output is +15V or -15V.

The serial interface supports TX, RX, and ground only – RTS/CTS hardware flow control is not supported. The following diagram illustrates the behavior of the TX and RX signal:

Open

The 3.5mm serial port has the following configuration (from the perspective of the player):

• Tip: Receive

• Ring: Transmit

• Sleeve: Ground

BrightSign players are DCE devices, so communication with another DCE device that uses a 3.5mm port would require a null-modem cable or converter that transposes the TX/RX signals. If the device communicating with the player is a DTE device with a DB9 serial port (performing asynchronous transmission), the serial cable should be wired as shown in the following diagram:

Open

DB9 RS-232 Serial

The RS-232 interface is a male DE-9 (more commonly referred to as DB-9) connector. The input to the chip accepts a range between +25V and -25V, so it is compatible with +12V/-12V signaling.

The RS-232 interface supports RTS/CTS hardware flow control, but no software flow control. The maximum cable length is 50 meters, and the total cable capacitance is 2500pF.

The following diagram illustrates the behavior of the TX and RX signal:

For details on pinouts, check the individual hardware pages: 4Kx42, XDx32, XDx30, HDx20, HDx22

Port Enumeration

Most standard serial devices connected to the DB9 or 3.5mm port will enumerate on port 0 of the player (on the HO523 player, they will enumerate on port 1).

Serial devices connected to a USB port will enumerate on port 2 of the player (on the LS424 player, they will enumerate on port 0). Additional USB-serial devices will enumerate on ports 3, 4, 5, etc. The enumeration order will remain consistent between reboots as long as the USB-serial devices are connected to the same player/hub ports. The enumeration order can be retrieved using the "usblist" command at the brightsign> shell prompt; otherwise it will need to be determined by testing the setup.

^* The 3.5mm serial ports on some older player models do not fully meet the TIA/EIA-232-F transmitter requirements. These units will interoperate with most, but not all, conformant EIA-232 receivers. Consult the hardware documentation for your player for full details.