• control MIDI equipment by computers or other equipment, which don't have a MIDI interface - like industrial controllers, PLC.

• expand professional media control equipment with a low budget MIDI interface.

• use software without MIDI drivers for control of MIDI equipment.

• use a MIDI sequencer or MIDI based control software for control of equipment with RS-232 interface.

The conversion process is bidirectional and transparent; i.e. data can be transmitted and received simultaneously in both directions.

Different modes of data handling are available:

• Direct baudrate conversion: No data bytes are modified, only the baud rate and connection technology.

• Transformation ASCII text <--> MIDI message: the value of any MIDI byte to be transmitted is entered as ASCII text at the serial interface. Vice versa, any byte received at MIDI IN is retransmitted at the serial interface in ASCII text format. This mode of operation is especially useful to run MIDI equipment by control software, which allows only transmission of "printable" ASCII bytes (7 bit ASCII). Furthermore it is a good tool to check MIDI equipment by means of an ASCII terminal.

• Transformation MIDI message <--> RS-232/RS-422 byte: MIDI messages are decoded by the Converter into serially transmitted bytes (8 bit length). Vice versa, any single byte received at the RS-232/RS-422 interface is composed into a specific MIDI channel message and retransmitted via MIDI OUT. This mode of operation preferably supports control of equipment with RS-232 interface by means of a MIDI sequencer, controller pad or MIDI keyboard.

• As a useful enhancement of this transformation up to 512 user defined strings can be created and stored permanently. Each of these strings may contain command sequences of up to 126 bytes length. These strings are triggered by specific MIDI channel messages to be transmitted from the RS-232/RS-422 interface or they are triggered by serially received bytes to be transmitted at MIDI OUT. Triggering is specified by a set of filter functions.

• As a little extra feature the Converter hardware is equiped with 4 analog inputs which may be used as digital I/O too and 2 transistor switches.

• 2 different command interpreters provide the means to combine the analog and digital I/O functions with serial and MIDI data. One interpreter is optimized for easy interactive control, especially to program the user defined strings. The other one allows to put simple standalone applications into practice by means of a programming language similar to 'C'.

Technical Details

At the front panel, the MIDI RS-232/RS-422 Converter is provided with a MIDI IN and a MIDI OUT connector.
No MIDI Through is available.
Different modes of operation and baud rates can be selected with a rotary switch.
The presence of supply power and data flow is monitored by a red/green dual LED.

At the rear panel separate connectors for RS-232 and RS-422 are installed.

• Standard baudrates of the RS-232/RS-422 interface are selectable: 2400, 4800, 9600, 19200, 38400 Baud and for special applications MIDI bitrate (31250) too. Transfer format 8N1.

• Driver circuitry for RS-232 and RS-422 on board.

• For each data direction a cyclic buffer memory is provided.

• 9-pin Sub-D male connector in DTE configuration (equivalent to a PC COM port). RTS/CTS handshake is optionally available.

• 15-pin Sub-D female connector for RS-422. At this connector additionally 4 analog inputs (combined with 4 digital I/O) plus 2 MOS switch transistors are wired out. For simple supply of external components the internal regulated voltage +5V, max 100mA is made available at this connector.

Electromechanical Features:

• Rugged aluminum case. Mechanical dimensions: length 8,3 cm (except connectors), width 11,3 cm, height 3,1cm.
  
  separate connectors for RS-232 and RS-422 interface (plus 6 I/O lines)

  Power supply:

  An in-plug adaptor for 230V AC with "europlug" is delivered along with the Converter. For special applications, other supplies with regulated or unregulated DC output can be used (min. current output 250 mA). The optimum supply voltage is 9 Volt, but up to 16 Volt are permitted.

User's Manual of the MIDI RS-232/RS-422 Converter  (PDF Format)