Digital audio point-to-point interconnection over gigabit ethernet originally developed by Sony Pro-Audio Lab and now owned by Klark Teknik. can be networked via dedicated routers, such as the Midas DL461 Audio System Signal Router, to provide channel-by-channel audio routing (like a patch bay), as well as packet switching for the auxiliary data messages. Routing is centralised, not distributed, giving better latency control, better reliability and finer routing granularity than distributed audio networks. It uses Ethernet frames transmitted over the physical layer only of the Ethernet technology – the cables and transceivers at each end. A deterministic protocol is used that is essentially a time-division multiplex (TDM) at the hardware level. This approach offers robust, low-latency and deterministic latency audio routing, with the benefits of a true packet-switched network for the control data. The frame-based method allows for simultaneously high channel counts and very low deterministic (fixed) latencies. At 96 kHz operation (as adopted by Klark Teknik and Midas to minimise latencies when converting between analogue and digital domains), HyperMAC offers 192 bidirectional channels with an individual link latency of four samples, or 41.66 µs. In typical implementations, an additional latency of two samples is incurred converting to an internal data format such as I²S, to give a total of 62.50 ?s. Currently HyperMAC only supports 96 kHz operation.