Coax Networking Guide
Short answer: MoCA 2.5 and DOCSIS 3.1 cable modems can share the same coax. The only conflict comes when your provider uses spectrum up to 1218 MHz, which overlaps the bottom of the MoCA D-band. The fix takes minutes: set every MoCA adapter to D-band High (1350–1675 MHz, LOF 1400 MHz), use a PoE filter that passes up to 1218 MHz, and turn off any second MoCA network in your gateway.
Key takeaways
- Cable systems traditionally stop at 1002 MHz; DOCSIS 3.1 can extend to about 1218 MHz.
- MoCA 2.5 D-Low (starting just above 1.1 GHz) can overlap that; D-High (1350–1675 MHz) stays clear.
- Use MoCA-rated splitters (5–1675 MHz) and a DOCSIS 3.1-compatible PoE filter.
- G.hn coax adapters are not suitable on a line that also carries cable internet.
Where the overlap comes from
MoCA adapters and cable modems were designed to share the same coax: the modem uses the lower part of the cable and MoCA uses the part above it. DOCSIS 3.1, the standard behind most multi-gigabit cable plans, can push the modem’s signal higher up the cable, and in some homes it now touches the bottom of the MoCA range.
| Signal on the coax | Frequency range | Overlap? |
|---|---|---|
| Cable TV and internet (classic) | Up to about 1002 MHz | ✅ No overlap with MoCA |
| DOCSIS 3.1 (extended) | Up to about 1218 MHz | ⚠️ Can overlap MoCA D-Low |
| MoCA 2.5 D-Low | From just above 1.1 GHz | ⚠️ Avoid if DOCSIS reaches 1218 MHz |
| MoCA 2.5 D-High | About 1350–1675 MHz | ✅ Clear of DOCSIS 3.1 |
Signs of a conflict
- Your internet speed drops or the modem reboots after you add MoCA adapters.
- The MoCA link is slower than expected or drops from time to time.
- The modem’s status page shows errors on its highest downstream channels.
Fix 1: move MoCA to D-band High
Kiwee D-band adapters can be set to run only in the upper part of the D-band, well above any DOCSIS 3.1 signal. Do this on every adapter in your network:
- Open the adapter’s web interface and go to the MoCA settings.
- Set the frequency band to D-band High (1350–1675 MHz).
- Set the LOF to 1400 MHz.
- Save and restart the adapter, then repeat on the next one.
- Check the result: MoCA link lights solid and internet speed back to normal.
All adapters must use the same band and LOF, or they won’t find each other. The KB-M3-03 product page has a step-by-step video of this setup.
Fix 2: use the right splitters and PoE filter
Splitters
MoCA-rated, 5–1675 MHz
Old splitters rated only to 1000 MHz weaken the MoCA signal. Replace them with MoCA-rated ones.
Point-of-entry filter
Passes up to 1218 MHz
Keeps your MoCA signal in and neighbors out, and often improves speed. An older 1002 MHz filter can block part of a DOCSIS 3.1 signal.
Amplifiers
Must pass MoCA
If a drop amplifier sits between rooms, check that it passes MoCA, or the signal will not get through.
Fix 3: check your gateway’s built-in MoCA
Many provider gateways (for example some Xfinity and Cox models) have MoCA built in. If it is switched on, it creates a second MoCA network on the same cable. Either turn the gateway’s MoCA off in its settings and use your adapters on their own, or use the gateway as the first node of your MoCA network, on the same band.
Two separate MoCA networks competing for the same frequencies are a common cause of slow links.
How to check that everything is healthy
Look at the MoCA link rate in the adapter’s web interface. On a good MoCA 2.5 connection it is typically around 3500 Mbps, which gives up to 2.5 Gbps of real throughput. Then run a speed test through the modem to confirm your internet plan speed is unaffected.
Which Kiwee adapters work with DOCSIS 3.1?
All Kiwee D-band MoCA 2.5 adapters coexist with DOCSIS 3.0 and 3.1 cable modems.
2.5GbE + PoE+
KB-M3-03
Powers an access point or camera: 30W at the port, up to 25.5W at the device.
2× 2.5GbE + PoE++
KB-M3-04
Up to 90W per port, 120W total, for two high-power devices.
Our G.hn adapters are not suitable for a coax line that also carries cable internet, because G.hn uses the same low frequencies as the modem. See MoCA vs G.hn.
Frequently asked questions
Does MoCA slow down my cable internet?
Not when it is set up correctly. MoCA and the modem use different frequencies. If your provider uses spectrum up to 1.2 GHz, switch the adapters to D-band High to keep them apart.
Do I need a PoE filter?
It is strongly recommended. It protects your network’s privacy, stops interference from neighbors and usually improves MoCA performance. With DOCSIS 3.1, make sure it passes up to 1218 MHz.
How do I know which frequencies my provider uses?
Check your modem’s status page: if it lists downstream channels above 1002 MHz, your provider uses the extended DOCSIS 3.1 range. When in doubt, setting MoCA to D-band High is safe either way.
Does MoCA work with Xfinity?
Yes. MoCA D-band adapters coexist with Xfinity’s DOCSIS 3.1 service on the same coax. If your gateway has MoCA built in, either turn it off or use it as part of your MoCA network, and use D-band High if Xfinity uses spectrum above 1002 MHz in your area.
Still seeing slow speeds?
Send us your modem model and a screenshot of the adapter’s MoCA status page, and we will help you sort it out.
