RJ45 in-line coupler

[Scott]

I am wondering: if I use one of these to extend my ethernet connection (well within the 100 metre limit) will it have any material effect on speed? Asking the question of Mr Google produces mixed views.

[Andy Burns]

Short answer, no.

[John Rumm]

IME they will work fine for data at 1GB/s

[Scott]

Thanks x2

[Davidm]

I'm doing it (for some years now). Works fine.

[David Wade]

The original 10Mhz Ethernet allowed you to have two connections. So switch<=>patch cable<=>trunk cable<=>patch cable<=>device.. ..I understand that at some point they added an extra connection, I believe because of POS machines, so adding an in-line coupler should not affect performance... Dave

[Brian Gaff]

Depends on the contact resistance I'd say, El cheapo bits usually tend to give issues at higher speeds, but I guess if things are left alone, then probably no issue, but the speeds have gone up a lot of late and some cabling may just not be that good. Brian

[John Walliker]

Adding a second device doesn't just involve adding some extra connectors and extending the cable. The intermediate device will contain a 3-port ethernet switch so the cable is not actually extended at all, not is an extra connector inserted. The cables between the intermediate device and the end device and the intermediate device and the distant switch are electrically independent. Simply joining two patch cables together with a coupler to get more length may not be ideal, but it usually works just fine. The most common problem is that the cables get disengaged or that the coupler falls apart. The standards allow for up to 10m of patch cables and

90m of "horizontal" cabling which means the bit built into the building. There will typically only be a metre or so of patch cable at the switch end, so up to 10m of cable at the user end will be fine. Most horizontal runs are shorter than the maximum, so in most cases patch cables can be much longer. 1Gbit/s ethernet can be just as reliable than 100Mbit/s, surprising as it might seem. They both operate over exactly the same frequency range, but 1Gbit/s uses more complex equalisers and echo cancellers. All speeds up to 2.5Gbit/s are fine over CAT5e or better cable at up to 100m cable length. CAT5e is specified up to 100MHz (and may have an attenuation as high as about 30dB at that frequency). Using higher spec cable such as CAT6 or the much better 6A will improve the immunity to interference.

John

[Theo]

Possibly not great for 10 gigabits/s, should be fine for 1 gig.

Theo

[The Natural Philosopher]

A well made connector will not result in much reflection. \thernet is driven at fairly high power over short to medium distances.

The original coaxial Ethernet was limited by time delays and collision avoidance: use of switches and a star network pretty much eliminated that so its really all about preserving the waveform over the distance now. Honestly i'd say long cables are more an issue than couplers.

[Andy Burns]

Some cat6 patch panels are actually constructed with back-to-back "keystone" RJ45 sockets anyway, so there are double the number of plug/socket connections compared to a punch-down wired patch panel.

[Vir Campestris]

Slightly longer answer: It'll reduce the range a bit. So long as you are well under 100m no problem at all. And you'd probably get away with it at full length too - there's quite a bit of headroom.

Andy