4MB SRAM (2 banks with 512K x 32 bit); Battery backup by on board lithium cell or external battery via P14; Battery monitor with interrupt on battery low; Additional 4 channel RS232 asynchronous serial interface; Programmable baud rates up to 115.2 Kbaud; Support of Rx, Tx, RTS, CTS and GND per channel; 64 byte receive FIFO and 64 byte transmit FIFO per channel, programmable trigger levels for FIFO's; ESD protected RS232 line driver/receiver up to 15KV according to IEC1000-4-2; DB25 female connector mounted in front panel; PCI I/O signaling voltage 3.3V and 5V; Operating temperature 0°C to +70°C