Most "my extender doesn't work" problems turn out to be cable problems. HDMI and KVM extenders push far more data down a twisted-pair cable than an office network does, so the cable type, its quality and how it is installed all decide the distance you actually get. Here is what each cable can do for AV, using the published ratings of real AV Access models.
The cable types in plain terms
| Cable | Rated bandwidth | Use it for |
|---|---|---|
| Cat5e | 100 MHz | 1080p extenders and shorter runs. Many 4K kits lose 10–30% of their range on Cat5e. |
| Cat6 | 250 MHz | The everyday choice for 4K extenders up to about 70m. |
| Cat6a | 500 MHz | Full-distance 4K (100m), HDBaseT 3.0, 8K and anything rated "Cat6a only". |
| Cat7 | 600 MHz | Same use as Cat6a, fully shielded, for electrically noisy sites. |
| Fibre (OM3/OM4 multimode) | Very high | Beyond 100m, between buildings, and around heavy electrical interference. |
Real distances by cable
These are the manufacturer's ratings for products we stock:
| Model | Cat5e | Cat6 | Cat6a / Cat7 |
|---|---|---|---|
| 4KEX40-KVM (4K60 KVM) | 35m | 40m | 40m |
| 4KEX70-USB-L (4K30 KVM) | 50m | 70m | 70m |
| 4KEX100-KVM (4K60 KVM, HDBaseT) | 90m | 100m | 100m |
| 8KEX100-KVM (8K / 4K120 KVM) | 90m | 100m | 100m |
| 4KEX100-L (4K HDMI, HDBaseT) | 70m | 70m | 100m |
| 4KEX100-BYOM (dual 4K + USB 3.2) | — | — | 100m (Cat6a U/FTP or F/FTP) |
For fibre, 4KEX300-F reaches 300m on duplex OM3 multimode fibre with LC connectors, and 4KIP500F-KVM reaches 550m on OM4.
Five installation rules that protect your distance
- Solid copper only. CCA (copper-clad aluminium) cable is cheaper but can't carry HDBaseT or 4K signals reliably. If the box doesn't say "solid copper" or "pure copper", don't use it for AV.
- One continuous run. Each coupler, wall jack or patch panel costs distance. HDBaseT works best on a single run from transmitter to receiver.
- Same termination at both ends. Crimp both ends to T568B and test every pair with a cable tester before the walls are closed.
- Keep it apart from power. Leave a gap from mains wiring and cross power cables at right angles. Near lifts, motors or dimmers, use shielded cable (U/FTP or F/FTP) with shielded connectors.
- Don't run it through a network switch. Point-to-point extenders need a direct cable. Only AV over IP products (HDIP100, 4KIP200, 4KIPJ200) connect through a switch.
When to choose fibre
- The run is longer than 100m.
- The cable goes between buildings, where lightning and differences in earth potential can damage copper.
- The site is electrically noisy: factories, broadcast trucks, stadiums.
- You want the cable to stay useful for future higher resolutions.
Troubleshooting a blank screen
- Swap in a short patch cable between the transmitter and receiver. If the picture appears, the long cable or its termination is at fault.
- Drop the source to 1080p. If the picture appears, the run is too long or the cable too poor for 4K.
- Check the power arrangement: on PoC and PoE kits, only one end takes the adapter.
- Reset the EDID setting to the default and reconnect the display.
Choosing an extender? Start with our HDMI extender guide or KVM extender guide.