Open Systems Manager (Front Cover)
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- VIDEO ADAPTER
| ETHERNET ADAPTER BOARD The Ethernet adapter board mounts at the rear of the server module because its input and output are to the Ethernet network via a cable connection to the NTSM01 termination unit. Ethernet connections are at the NTSM01 termination unit. The Ethernet controller integrated circuit integrates the ISA bus interface, Type 10BaseT interface, and attachment unit interface (AUI). For Type 10BaseT cable, direct connection is possible because the termination unit cable and Type 10BaseT cable have the same characteristic impedance. There is also an isolation transformer/filter on the path of the transmit and receive data routes on the adapter board. Additionally, the receive path on the adapter board has characteristic impedance matching cir- cuits. The AUI interface on the adapter board requires isolation and active circuitry on the termination unit in addition to termination circuits at the end of the termination cable. The termination unit separates the AUI interface into a Type 10Base5 interface (thick Ethernet) and a Type Base interface (thin Ethernet). The receive path on the adapter board for the AUI interface also has characteristic impedance matching circuits. VIDEO ADAPTER The video adapter board mounts at the front of the module so that the video connector is accessible at the module faceplate. The board contains one megabyte of video dynamic random access memory. All timing signals are generated internally to the video controller therefore, only a reference frequency is required. The video controller uses peripheral input/output (PIO) transfers and requires no interrupts or direct memory access (DMA) activity. The board is fully SVGA compatible. |