Technical data

www.asti-usa.com ASTi DACS: Operation & Maintenance Manual (Version 4, Rev. B.1)

Indicator Lights

There are two indicator lights on the RIU - the sync light (a green LED) and an error light (which

is a red LED). Both are located next to the TDM RJ-45 connectors (see drawing in appendix D).

The error light will come on steady if no sync signal is being received by the RIU. (For example,

when the RIU is powered on, but not plugged into the TDM loop). If the red LED is ﬂashing, then

the TDM ring has sync pulses, but the RIU cannot synchronize with the Model Builder software.

The RIU must synchronize with a clock signal on the TDM ring, and cannot pass any sound or

data until it has done so. At power-up, the RIU attempts to synchronize. If the green LED is rap-

idly ﬂashing, then the RIU’s physical address is higher than what the model supports.

When the RIU is synchronized, the sync light will blink at 1 Hz. The sync lights of different RIUs

might be out of phase - one being on while the other is off. This is normal. At higher sample rates,

the green LED will blink at a faster rate.

Audio I/O

Audio input is capacitively coupled and balanced with an input impedance of > 1kOhms.

Input gain for each channel is settable to 1, 10, 100 or 1000 by changing a jumper on the circuit

board.

RIU Version 4.1:

The maximum input voltage is 4.5Vp-p.

The maximum output voltage power is 1W RMS into a bridge-connected 8! load. When driving

single-ended loads, the maximum output power is 250mW into an 8! bridge load.

Digital Input

Each digital input is a contact sensing input. It is triggered when the DI (pin 3) is shorted to one of

the grounds (pins 5 or 8). The DI input is connected to an internal pull-up resistor to 5V. To use a

DI circuit, connect a single-pole/single-throw switch between DI and a ground pin.

The model will respond to the digital input within one model frame. However, the digital input

will not respond to more than one change in a 50 ms period.

Digital Output

The digital output, when active, shorts the DO (pin 1) to ground. DOs are opto-isolated. The digi-

tal output will respond to a change in the model within one frame. However, it can not be changed

more than once in a 50 ms period.

See also ASTi application note for interfacing to RIU DIs and DOs.