1760

#29753
Profile photo of ahjeff
ahjeff
Moderator

Hi All

Gigabit Ethernet is designed to work in existing Cat5/Cat5e/Cat6 infrastructure, at up to 100 meters. The problem with this specification from an audio point of view is that a certain bit error rate is allowed at this length. For most IT applications, any transmission errors are recovered by TCP/IP, by retransmitting the information. With Dante or any low latency multichannel audio over Ethernet protocol that I’m aware of, bit errors will always correspond to missing or repeated audio samples at the receiving device, as there is not time to go back and wait for the sample to be transmitted again. For this reason, it is not safe to assume that 100 meters (or any particular length, really) will be error free in all scenarios. For ACE, A&H manufacture every device using the same hardware, so we are able to approve a list of cables that all work to a certain distance. In the case of Dante, this is not really possible, as laptops, switches, and other devices you may be using, can use any of dozens of possible Ethernet interface chips, creating hundreds of possible combinations of hardware that would all have to be tested if we were to be able to gurantee some particular cable type and length will work without errors.

This is not all that helpful for you guys trying to set systems up. Assuming that good quality cable is being used, the main cause of errors will be poorly (I really mean ‘not perfectly’ here) terminated connectors, so if you have a longer cable that doesn’t seem to work properly, you could try recrimping the connectors, making sure to only untwist the bare minimum of each conductor pair, and to get the ends of the conductors right to the end of the RJ45 plug (you can check this by holding the end of the plug up to the light and looking to see that all the shiny conductor ends reflect together). Another thing you might be able to try is to use the cable diagnostic feature that some Ethernet interfaces provide as part of their software drivers. The more sophisitcated implementations will tell you if there are any imperfections in the cable simply by running a short test with the cable plugged into the computer.

In general, with good quality cable and Ethernet hardware, you should be able to run 100 meters and never have an error. I suppose I just wanted to explain why you can’t simply look at the Ethernet spec and say “100 meters will work”, no matter what.

Hope this helps.

Cheers

– Jeff, A&H