User Manual
AES/SPDIF Connector Conguration
The -pin D-type connector labeled AES/SPDIF can be congured either as an AES or S/PDIF dedicated output using the AES/SPDIF
switch next to it. When operating the connector in AES mode, an AES cable is required. When operating in S/PDIF mode, the S/PDIF
RCA cable should be used, which automatically sets the output stream to consumer mode.
The Wire/ Wire switch selects -wire or -wire mode for the AES output as follows:
1-wire mode
Selected with the switch in the ‘out’ position. The AES connector transmits two channels of AES data simultaneously for all sample
frequencies from . to kHz, over a single wire.
2-wire mode
Selected with the switch in the ‘in’ position. The AES connector transmits one channel of AES data only per cable, for all sample
frequencies from 6kHz to kHz. The reason for the two modes is that older equipment with 6kHz and kHz AES inputs can
only receive speeds up to kHz by using both digital channels of a single AES connection (known as ‘-wire’). Therefore, one AES
channel can send only a single channel of digital data. This switch makes the ISA One useable with both old and new equipment.
Word Clock In and Out
The internal ADC can be synchronised to an external word clock. By pressing the front panel EXT sync switch, the ISA One can be
switched to lock to either standard external word clock or 56x external word clock. Either type of external word clock should be
connected to the ISA One ADC card at the WORD CLOCK IN BNC connector on the rear panel.
The WORD CLOCK OUT BNC connector either regenerates the external word clock connected at the word clock input connector
(if locked to an external clock source) or transmits the internal sample frequency of the ADC card (if the ISA One is acting as
word clock master). Where the ISA One is being used as a slave device within a larger digital system, the WORD CLOCK OUT BNC
connector can be used to pass on the external word clock signal to the next device. When the unit is not slaved to another device and
is in internal clock mode, the word clock output connector outputs the sample frequency selected on the ISA One front panel (see
next section).