Crystal Vision
Introduction
Crystal Vision
Installation
Signal earthing
Audio inputs are designed to have floating ‘signal low’ connections for cable
screens, with internal RC networks connected between cable screens and
chassis ground. This helps reduce the risk of high earth currents when AC
power is induced into the cable, or when an offset voltage exists between the
product chassis and the local signal source ground or chassis.
The internal RC network components fitted in the DACA214 PCB are as follows:
Component
Signal low (screen)
Chassis ground
1µF capacitor
10K ohm resistor
AES-1LO / AES-2LO AES-
1LO / AES-2LO
PCB GND
PCB GND
Note:
Video and audio output cable screens are normally hard-wired directly
to local chassis ground.
Using GPIs
GPI input assignments
The DACA214 supports four GPI input lines, which are assigned functions as follows:
GPI
Effect when GPI input is asserted low
GP1-1
Changes AES1 from Xtal Mode to Auto Mode
GP1-2
Changes AES2 from Xtal Mode to Auto Mode
GP1-3
Swaps AES1 input circuit with AES2 input circuit to exchange the two
stereo audio outputs one with the other
GP1-4
Changes dual input circuits to just one single AES input feeding all audio
outputs. The unused AES input will be disabled and therefore silent.
The GPI inputs override the switch settings and remote control settings, unless
the existing setting selects the same operation, as the GPI input would have
done, in which case there is no change of operation.
Each input looks like a TTL/CMOS input and has a 10k pull up to +5V, and is
‘asserted’ by pulling down to 0v.
GPI output assignments (alarms)
The DACA214 supports two GPI output lines, which are assigned functions as follows:
GPI
Alarms are active when asserted low
GP1-5
AES 1 Alarm - loss of input and silence detected
GP1-6
AES 2 Alarm - loss of input and silence detected
DACA214 User Manual R1.9
27
04 February 2019