More affordable alternative to "medical ethernet data isolator"? - Page 1
Forum section: electronics / beginners

author: sam1275
author_rank: Frequent Contributor
timestamp: May 17, 2015, 06:10:17 am
content: Hi everyone, I want to physically isolate (no direct electronic connection) a few RJ45 cable while remain Ethernet data pass through, and I found some brand making "medical Ethernet data isolator" which meet my need perfectly, but they are more expensive ($100-200 per) than I expected, how can I get any cheaper (but not crappy please) alternatives? Thanks!PS: I have a MikroTik router which provided a POE module, is that already isolated?

author: Rerouter
author_rank: Super Contributor
timestamp: May 17, 2015, 06:16:02 am
content: ethernet to fibre media converters on both ends?to point out the obvious ethernet is magnetically isolated at both ends, it just comes down to what isolation voltage you desire,

author: sam1275
author_rank: Frequent Contributor
timestamp: May 17, 2015, 06:27:52 am
content: Quote from: Rerouter on May 17, 2015, 06:16:02 amThank you, I also thought that ethernet port should have a isolation transformer inside, but I measured the resistance among ports on a switch is not infinite, maybe because it's a cheap D-link one?

author: SeanB
author_rank: Super Contributor
timestamp: May 17, 2015, 06:37:57 am
content: POE is not isolated, as it uses the data pairs to provide DC power. If you want isolation just get some POE injectors/extractors, as these have the required magnetic transformers and provide on the one side an isolated output.

author: sam1275
author_rank: Frequent Contributor
timestamp: May 17, 2015, 09:23:21 am
content: Quote from: SeanB on May 17, 2015, 06:37:57 amYes, I did mean POE injectors, so they are isolated between the to RJ45 port/jack?

author: SeanB
author_rank: Super Contributor
timestamp: May 17, 2015, 11:32:55 am
content: There is isolation on the non POE side, as they have to remove the DC component on the wiring. Depending on the device the insulation could only be around 300V or so, but should be enough. Some however do bond the centre taps on the transformer on the output to terminating resistors, you probably would have to replace them with some small chip capacitors ( around 10n 1kV) if you need more, or just remove them.

author: sam1275
author_rank: Frequent Contributor
timestamp: May 17, 2015, 03:12:31 pm
content: Quote from: SeanB on May 17, 2015, 11:32:55 amI just measured the injector module, the to RJ45 is not infinite ohms...

author: SeanB
author_rank: Super Contributor
timestamp: May 17, 2015, 05:28:30 pm
content: This looks like it is going to have integrated magnetics, and isolation between input and output.http://www.ebay.com/itm/POE-Module-Injector-Over-Ethernet-switch-router-for-IP-Camera-4-LAN-Power-port-/371278252371?pt=LH_DefaultDomain_0&hash=item5671e88953

author: sam1275
author_rank: Frequent Contributor
timestamp: May 18, 2015, 07:43:13 am
content: Quote from: SeanB on May 17, 2015, 05:28:30 pmThank you, but I don't want Chinese no-brand products...I just got a new idea: I can use two power line ethernet adapter to bridge them, but I need to make sure that there's good isolation inside a quality one. I got the following page:http://www.dslreports.com/forum/r26379325-Powerline-adapterIt seems ok, can anyone help me verify this?