AES47 (IEC 62365) is an open standard that specifies a method for packing AES3 professional digital audio streams over Asynchronous Transfer Mode networks. The details of these standards can be studied at [1] by downloading courtesy copies of AES47-2002, AES-R4-2002 and AES3-2003. The change in thinking from traditional ATM network design is not to necessarily use ATM to pass IP traffic (apart from management traffic) but to use it in parallel with standard Ethernet structures to deal with extremely high performance secure media streams. From work carried out at the British Broadcasting Corporation’s (BBC) R&D department (see [2]) it has been established that this approach provides the necessary performance for professional media production. AES47 has been developed to allow the simultaneous transport of a large number of AES3 linear audio streams at different sample frequencies. AES47 can support any of the standard AES3 sample rates and word size.