MULTIDROP COMMAND CHAINS
Gating off the response transmitter in a controlled port is an effective and transparent technique to resolve bus contention in a multi-drop command chain. In such a mapping, the controlling device sends commands to multiple destinations, but only one destination is allowed to respond. All other controlled-port transmitters are gated off. By design, the NV3128 controller allocates the response transmission path to the first target connected to the source, therefore the user designates the responding machine by the ordering of his take salvo.
1.3 I/O
A passive connector-interface backplane couples the active I/O modules and their external connections. Active modules can thus be removed without disturbing external cabling.
Data port connectors are RS-232 9-pin D. Video reference input ports are BNC. A female, 9-pin D connector recieves the serial router control system cable, and a 37-pin female D connector implements a parallel router-control interface (older frames only). Both control interfaces and both reference inputs provide unbuffered loop-through connectors.
1.4 PHYSICAL
Physically, the NV3128 frame installs in a 19" EIA equipment rack. Its aluminum frame requires no additional cooling, and will operate in ambient temperatures in the range from 0-50 degrees celcius. The 8 rack-unit high frame houses two backplanes, one for inter-module signal traffic, the other mounting I/O connectors. The active modules are inserted from the front of the frame. The modules consist of:
·Crosspoint Assembly (1) EM0041-XX
·I/O Assembly (2 - NV3128, 1 - NV3064-D) EM0040-XX
·Universal Control (1, redundant 2nd optional) EM0134-XX
·Power Supply (1, redundant 2nd optional) PS2001-01
