Option# X453A / X450A. Option X453A replaced option X450A in Sep 1992. Option X453A included 501-1881. 32-Bit SBus Connector. Manufacturer: Sun Microsystems. BNC External Connector. The Sun-4/75 supports one internal 207MB or 424MB disk drive if the Ethernet MAU draws current from the +12Vdc output to Pin-13.
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