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9. Communication Module R763768
Remote XLR connection
•
The direction of communication is determined by the RMT_DIR line. A low puts the interface in receiving mode, a high in
transmitting mode. All data is put on the RMT_DATA line.
•
The TTL level of the data is translated into a differential voltage by I6 and is then superimposed onto the ++24V supply by
transformer T1. Capacitors C14, C15 and C16 block the DC current in order not to saturate the transformer.
•
Because of the transformer it is also necessary to hold the DC level of the signal constant. That is why a zero bit is transmitted
as half the bit-time a low level and half the bit-time a high level. This is achieved with a mmv of I8 (pin 1-7). In receiving mode
a zero bit is stretched to the full bit-time by the second mmv of I8.
•
Because of the fixed delays of I8 the communication baudrate is also fixed to 57600 baud.
Power Supply
•
The main power supply is the ++5V coming from the SMPS. It is protected against overvoltage by the transorb Z3.
•
The ++24V from the SMPS is used for supplying power to the comm port and the remote XLR port. They are separately
protected against short circuit by the PTC fuses PT1 and PT2.
•
The ++9V for the comm port and IR wired remote is taken from the ++24V. It is stabilized and short circuit protected by I7.
Ethernet LAN controller for PC card
An Ethernet LAN controller, IC10 CS8900A, is provided on board. This offers a 10-base T input connection to connect the projector
to the corporate network (LAN). Thanks to the optional network interface, the SLM projector becomes an IP-addressable device.
The CS8900A includes on-chip RAM, 10BASE-T transmit and receive filters, and a direct ISA-Bus interface with 24 mA Drivers.
Communication Interface R763766
Controller
Serial Port
Image 9-4
DIMM-PC interconnection
Block diagram info:
•
Green LED: detection of the presence of a valid link.
Yellow LED: detection of network activity
•
Galvanic separation with transormer T2
•
Serial port with the Controller: RXD_SBC, TXD_SBC........
•
Module detection with Q12 & Q13: when SYSCLK is presence, the transistor Q12 is saturated whereas SBC_PRESENT is
high.
•
A lithium cell ensure real-time clock for the DIMM-PC.
58
ISA Bus
DIMM-PC/520
Lithium cell
Xtal
20MHz
LED Green
CS8900A
T2
Ethernet
Controlle r
LED Yellow
R5976820 SLM R12+ PERFORMER 08/03/2005
RJ-45
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