On Tue, Mar 23, 2004 at 10:27:02AM +0000, Daniel James wrote: > Currently its about 18 miles away, but I might convert a building in > the garden for recording purposes. Do you know what the limitations > on the length of S/PDIF cables are? http://www.epanorama.net/documents/audio/spdif.html : S/PDIF (IEC-958) uses 75 ohm coaxial cable and RCA connectors. 75 ohm coaxial cable is inexpensive, because it is the same cable as used in video transmission (you can buy a video cable with RCA connectors to connect you S/PDIF equipments together). Coaxial S/PDIF connections work typically at least to 10-15 meter distances with good 75 ohm coaxial cable. [Optical TOSLink] Because high light signal attenuation in the Toslink fiberoptic cable, the transmission distance available using this technique is less than 10 meters (with some equipments only few meters). I wouldn't normally do your Googling for you, but I was quite interested in the answer myself :-) That link also mentions the AES/EBU standard, which uses the same signal timing but higher levels and will therefore travel greater distances: "AES/EBU signal transmission work for few tens of meters with a good cable." - The cable has to have 110 ohm characteristic impedance. I'm also interested in the possibility of feeding S/PDIF over structured cabling using CAT 5 cable. Has any one tried this? I wonder how far it would go with suitable impedance conversion. 50/75 ohm transformers would also give electrical isolation. -- Anahata anahata@xxxxxxxxxxxxxx Tel: 01638 720444 http://www.treewind.co.uk Mob: 07976 263827
