The MESP 02 interface card is part of the series of SBX standard extension modules intended to increase the possibilities of Multibus type cards. It brings together 24 programmable input/output lines on a single-width module.

The MESP 02 module is in the form of a 94 x 72 mm card equipped with an SBX male connector for connecting to the host card and a 2 x 25-pin insert connector (or HE10 as an option) for external links.

The module comprises:

• A PPI P82C55A box (Programmable parallel interface unit)
• 4 14-pin supports allowing the assembly of TTL output circuits, of the type chosen by the user (even obsolete resistive networks of type DIL)
• 4 5-pin supports allowing the assembly of resistive networks, type SIL, input recall (validation of the recall requires one jumper per line)
• A bidirectional inverter circuit, fitted to port A, and mounted on a support to possibly be replaced by a non-inverting circuit
• A J1 insertable connector (2 x 25 pins, 2.54 pitch) grouping together all the input/output signals with pinout identical to the connectors of the Multibus cards (except for the signals that do not concern the I/O lines)
• A matrix of jumpers that allows the choice of
  • the assignment of lines of the port C
  • interrupt sources to one of the 2 interrupt lines of the SBX bus
  • the polarity of the control signal of the direction of the bidirectional circuit