ONELAN | Support

Overview

This document describes the RS232 Input and Output capabilities on a ONELAN Net-Top-Box (NTB) media player. This document refers to NTBs running V6.2 software onwards.

Most products in the NTB range have a single RS232 port presented on a 9 way ‘D’ type plug. This port can be used for a number of purposes:

Sending user defined RS232 strings.

Sending user defined RS232 strings at specific events or at PlayList positions. The strings must be defined as their byte values expressed as separated hexadecimal nibble pairs. E.g. 3a 3b 3c 0d 0a. It is up to the user/installer to create the strings in accordance with the needs of the attached device(s). Sending of RS232 commands is unaffected by the state of any of the RS232 control lines - see below. See Table 1 below for port pin-out.

Receiving RS232 strings.

The most recently received string is reported by the NTB in the Home->Setup->RS232 Outputs->Items Tab->Edit->Last Response. At software version 6.2 (and lower), the NTB provides no interpretation of the strings. Receiving RS232 commands is unaffected by the state of any of the RS232 control lines - see below.

Control Line Inputs – from V6.2 software onwards

The NTB’s RS232 port has 4 input lines that may be used to take in binary events such as contact closure or signals from other devices. The available lines are:

Clear To Send – (CTS)
Data Carrier Detect - (DCD)
Data Set Ready - (DSR)
Ring Indicator - (RI)

The lines do not affect the operation of the RS232 Send and Receive strings.

Each input line must first be enabled (Home->Setup->Touch and RS232 Inputs) and given a name for future reference – see below.

Each RS232 Input Item may then be included in a PlayList and used to generate an NTB ‘AdvanceTo’ or ‘Change Layout’ on a user defined transition of the line. The AdvanceTo or Change Layout commands can be configured to change the media being played by the NTB.

Control Line Output - from V6.2 software onwards

The NTB has the ability to control the output state of the RS232 DTR and RTS lines. The lines are controlled by RS232 Output Items that must be created and may appear in PlayLists. The RS232 Output Items can assign the state of one or both RS232 output lines and optionally a string of characters to be output. The RS232 Output Items are given names in order to make the intended usage clearer in the NTB’s configuration.

The pin assignment of the 9 way ‘D’ Plug is as follows:

Pin	Direction	RS232 Name	NTB Quiescent State
1	Input to NTB	DCD	Hi impedance
2	Input to NTB	RxD	Hi impedance
3	Output from NTB	TxD	-ve Voltage level
4	Output from NTB	DTR	-ve Voltage level
5		Sig. GND
6	Input to NTB	DSR	Hi impedance
7	Output from NTB	RTS	-ve Voltage level
8	Input to NTB	CTS	Hi impedance
9	Input to NTB	RI	Hi impedance

Table 1 – Port Pin-out

Electrical Interface

For historical reasons, The RS232 standard uses a variety of terminology to describe its signal status. I.e
Lowered = Negated = Logic 1 = -ve voltage = Off = Marking
Raised = Asserted = Logic 0 = +ve voltage = On = Spacing

The ONELAN NTB uses voltage level in order to describe line status since this is the only explicit identification.

Inputs have:

hysterysis (generally of about 0.5V)
a threshold level of about +1.5V
an input impedance of about 5K Ohms connected to Gnd. – i.e. defaults to a -ve voltage state with nothing attached
an acceptable input range of +/-15V

Outputs have: