400-135-602 Abaco Systems Cable Assembly

Share memory and special purpose cards between a VMEbus system and a MULTIBUS I computer with Bit 3's easy-to-use, cost-effective Model 422 Adaptor. The Model 422 Adaptor provides high-speed data transfers between the VMEbus and MULTIBUS I and requires minimal software support. The Model 422 Adaptor allows both systems to directly address resources on the other system as though they were local, random access reads and writes to be executed between systems, and blocks of data, I/O commands, and interrupts to be passed between systems.

The Adaptor can be configured in a transmitter/receiver or transmitter/transmitter relationship. In a transmitter/receiver configuration, the Adaptor card in one system functions as a slave device allowing memory references to it to pass to the other chassis. When configured for transmitter/transmitter capability, both systems can function as a transmitter and appear as a bus master processor on the other system. No intermediate software drivers are required for the bus master to communicate with memory or I/O on the other system.

With the Bit 3 Adaptor, each bus operates independently. The timing of the two buses is linked only when a memory or I/O reference is made to an address on one system that translates to a reference on the other. The integrity of the interface between the Adaptor cards is maintained by parity checks on address, control, and data lines. Other Bit 3 Adaptors, supporting a wide variety of buses, can be used with Model 422 Adaptors to connect multiple computers and systems in star, daisy-chain or modified star/daisy-chain configurations.