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This cabling supplement to intended to accompany 'Using Routers' and anything else that uses UTP cables for any reason, such as 'The Thing', or perhaps for CAN bus.
If you don't already have a working knowledge of UTP cabling from past experience, it may seem a bit daunting - but it''s not expensive or difficult once you know what to do.
So that's what this article is about... showing how anybody can cheaply and easily create their own UTP (Unshielded Twisted Pair) cables tailored for their needs.
We'll be using the common Cat5E spec of un-shielded cable which has 4 pairs of twisted wires, and allows for cable lengths of up to 100m..
When used for 100Mbps ethernet it only uses 2 of the 4 pairs, leaving the other 2 pairs available, eg: for supplying power to a remote router.
The same Cat5E spec cable can also achieve Gigabit (1000Mbs) ethernet data rates by using all 4 pairs.
Even though all 4 pairs are used for a Gigabit network, POE Injection (Power Over Ethernet) allows a DC offset down the wires to supply power to remote low-current devices such as Routers and IP Cameras etc typically 5V, 12V, 24V, 48V according to device needs).
A 300m (1000ft) box of Cat5E UTP cable costs around 40 quid - it is commonly grey, but also available in various colours, which can be handy for quickly telling cables apart, eg: when pulling multiple cables at a time through trunking etc. (I use a box of grey for network, yellow for CCTV, blue for sensors, green for other extenders)
(each of the 3 locations on my property have UTP cabling to supply 2 different subnets, CCTV video, Sentry Alarm audio, IR extenders, and some other stuff).
Where several cables converge to the same location, they can be identified by using an audio signal injector at the remote end, and checking for signal at the other end using a non-contact tracer probe. The signal injector/tracer pair costs about a tenner - some have RJ45 and RJ11 sockets for plugging in cables directly, and some also have a croc clip adapter for connecting to any type of wiring, which can be useful for tracing wires in vehicles or hidden behind walls etc.
Bags of 100 gold-plated RJ45 plugs costs less than a quid, and an RJ45 crimp tool costs less than 7 quid.
Bags of 100 optional protective strain-relief boots can prevent the RJ45 plastic locking lugs from being accidentally broken off, and different coloured boots allow cable ends to have matching colours for easy at-a-glance identification. Coloured RJ45 plugs are also available, allowing for many different plug and boot colour combinations.
Here's a Youtube video which explains how to crimp the connectors to the cable.
Note that the green pair is spread apart to deliberately straddle either side of the inner blue pair... it is a bit fiddly, but not difficult.
Cheap LAN cable testers are available for less than a fiver which sequence through all 8 conductors in turn checking for faulty or out-of-sequence connections. Note that if cables allow the transmitter and receiver units to be viewed side by side it will be obvious if one or the other ends LEDs are out of sequence, but if only viewing from one end it is possible to miss an out-of-sequence shown at the other end.
Click the Play icon in the first pic of this15 quid combined signal injector/Tracer plus LAN cable sequencer to see how easy it is to trace, then test, unmarked cables.
That pretty much covers what you would need to crimp plugs to cables, but if you wish to connect to RJ45 sockets or patch panels you may need a 'Krone' punch-down tool.
Accessories
RJ45 female to female couplers can come in handy for joining cables together, or changing a male end to a female for plugging in male accessories - but it's worth paying for gold-plated contacts to prevent them corroding from humidity and becoming high resistance with a resulting loss in speed, performance and reliability.
3-way couplers could be used to join 2 cables if necessary, but they would more typically be used as splitters for signals which do not need handshaking (audio, video, etc).
I plan to use them to link UTP cables as a convenient twisted pair plug-in CAN bus with the 3rd outlets connecting to the CAN nodes, using POE to supply power if needed.
RJ45 to screw terminal adapters can be used as breakouts for monitoring or measuring any of the UTP wires when necessary. They are also a useful way to connect to other non-RJ45 items (eg: CAN transceivers, PIRs etc) without needing to cut off the plugs.
Many types of RJ45 adapters (baluns) are available (typically as matched transmitter/receiver pairs) which use UTP cable to extend different types of signals up to 100m. For instance, I have baluns with BNC and/or RCA connectors for connecting to CCTV cameras, usually they also have DC power jacks for supplying power to the remote cameras, and some also have RCA audio connector for cameras which have built-in microphones.
I also have RJ45 baluns for extending USB, IR, VGA, HDMI, and other things.
But this clever gizmo takes it a step further by combining 4 channels of Audio and Video and IR extenders all in one unit.
This allows a central location to distribute audio and video to 4 remote destinations each up to 100m away, and returns IR signals from remote controllers at any of the remote locations to control the central AV equipment.
It even has a local pass-through AV output which allows connecting another unit to supply even more remote locations if needed.
My Sentry Alarm (The Thing) uses UTP to supply 12v DC to remote PIR and beam-break sensors 50m away and return their trigger signals back to the Sentry.
All the CAN bus wiring carried out during the original ambulance conversion of my ex-ambulance camper was done using UTP, and I will be adding my own UTP CAN bus, and maybe 'can' even link them together.
So although it's only wiring, the ability to do some UTP cabling can open up many possibilities.
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