Depending on the setting of the front panel push button switches, each ADAT Lightpipe input can be inserted into the stream going out either or both or neither CAT5 cable, and each ADAT Lightpipe output may be tapped from either one or the other CAT5 cable. In any case, each input can only appear on correspondingly numbered outputs on other AudioRail units (ADAT1 to ADAT1, ADAT2 to ADAT2, etc.)
The AudioRail ADAT rx32tx32 product works with Alesis ADAT Lightpipe, running at either 44.1K or 48K sample rate. It also works with the 88.2K/96K ADAT Lightpipe doubling format (which accomplishes its purpose by simply doubling up on the normal 8 channels available, to yield 4 audio channels per lightpipe, instead.) AudioRail will not work with the old ADAT 8-track tape machines that have variable tape speed controls.
Synchronization is on a per ADAT Lightpipe channel basis, from end to end. Each of the eight channels (four inputs and four outputs) is completely independent of the other. If synchronization is required between channels, this must be accomplished at either end, as appropriate. Each ADAT Lightpipe stream follows the timing of its source. Consult the instructions for and follow the corresponding guidelines of the equipment connected at each end to determine what, if any, synchronization needs to be done.
ADAT Lightpipe is based on Plastic Optical Fiber (POF) Toslink connections which are very economical, compared to conventional glass fiber optics used in telecom and computer networking applications. However, it is important to keep in mind that this optical signal degrades profoundly with distance. Different brands of plastic optical fiber yield different maximum distances. By convention, 10 meters (33 feet) is called out as the limit. Because of the eight channel density of the Alesis ADAT Lightpipe protocol, ADAT Lightpipe connections are the most susceptible to degradation. Keep these connections as short as practical. Corruption of data will be apparent as harsh crackling noises and static (not hiss, hum, loss of high end frequency response, or subtle sonic variations, as experienced in traditional analog connections). If corruption occurs, then use shorter or better quality fiber connections. AudioRail uses the highest grade Toshiba Toslink transmitters and receivers, designed for up to 15 Mb/s NRZ data rates, to maximize margins on the AudioRail end. The quality of mating professional audio products and the quality of plastic optical fiber cables on the market vary from product to product, which altogether determines maximum deployable length of the plastic fiber connections. Be advised that this could be either more or less than 10 meters (33 feet).