I/O Configuration 64-Bit TTL Digital Input/Output: Supports 8 independent I/O ports, each 8 bits wide, individually programmable in direction (input/output). Output capacity: 64mA sink current (maximum), 15mA source current. If the open-collector output is selected, all 64 bits support only the output mode. Input/output interface: Dual 64-pin connector (according to DIN41612 standard), supporting differential or single-ended signal transmission.Electrical characteristics Logic levels: TTL compatible (0 V to 5V). Transceiver Model: Logic Level I/O uses the SN74AS645 octal bus transceiver. The open collector option uses the SN74AS641 transceiver.Addressing and data transfer addressing scheme: support 8-bit, 16-bit and 32-bit boundary addressing. Unlimited short I/O address mapping via address DIP switches, compatible with VMEbus' short supervisor or short non-privileged I/O modes. Data transmission mode: support 8-bit, 16-bit and 32-bit parallel data transmission.Built-in test function Offline/online fault detection: Test mode is enabled by writing to the control and status register (CSR), and the output goes tri-state (TRI-STate) to quarantine the signal. Two test mode bits are provided to allow independent testing of 32-bit I/O for each connector.Fault Indication: The front panel Fail LED illuminates on power-up or reset and can be programmed to turn off after successful diagnostics.Physical and environmental form factor: Double-height VME half-length card (160mm × 100mm). Operating temperature: -20 ° C to + 85 ° C (industrial version). Storage temperature: 0 ° C to + 55 ° C (commercial version).Compatible bus standard: Fully compatible with VMEbus specification ANSI/IEEE STD 1014-1987. Address Mapping: Supports contiguous I/O address configuration to save memory space. CSR address switches can be mapped to contiguous memory locations.