Envision Peripherals NV3128 - Manual (Page 68)

NV3128 RS-422A Machine-Control Data Routing Switch 4-6
4.2.3 CROSSPOINT MODULE: ASSY EM0041-XX
INPUT DATA
Input signal data flows into the crosspoint module from the signal
backplane. The data is resistor coupled into buffer/driver integrated
circuits, then passed onto the data bus for application to the crosspoint
ICs.
Control data from the Command Interpreter arrives through the
backplane and into a similar circuit. The control data contains two
buses: a register bus that addresses specific crosspoint outputs and a
data bus that holds the address of the input to which an output will
connect.
CROSSPOINTS
The crosspoint module uses four 64x64 crossbar ICs to cross-
connect any of 128 outputs with any of the 128 inputs in the crosspoint
matrix. The chip’s address registers are double buffered. Control
information is stored in a load register, then transferred to the active
register on arrival of a strobe pulse, the signal "BNKLDI".
OUTPUT DATA
Outputs from the crosspoint chips are driven over the signal backplane
to the I/O modules by 16 octal buffer/line-driver integrated circuits.
MISC:
A submodule and associated circuitry process raw DC from the power
supply to produce a carefully regulated and current limited +5VDC for
distribution across the module.