Simple answers to common Wi-Fi questions
Type your problem in your own words below. Every answer says what to check, what to leave alone, and when it's time to call someone for help.
6 answers found · last checked 17 August 2026
My internet phone has one-way audio.
One-way audio commonly points to NAT/firewall or blocked RTP media, not Wi‑Fi speed alone. Test the ATA/phone by Ethernet and review SIP/NAT design.
VoIPCalls sound robotic or break up.
Packet loss, jitter, latency and upstream congestion cause broken voice. Test wired, pause uploads and capture a failing call time.
VoIPMy ATA will not register after changing router.
Check DHCP/IP, DNS, cabling, SIP credentials and whether double NAT, CGNAT or firewall/ALG behaviour changed.
VoIPWill my digital phone work in a power cut?
Usually not unless the ONT/router/phone equipment has backup power. Ofcom requires providers to address emergency-call resilience, especially for at-risk customers.
VoIPCan I plug my old phone into an ATA?
Often, but compatibility depends on tone/ringing, connectors and the VoIP service. Alarms, fax, lifts and telecare need explicit compatibility testing.
VoIPWhy does fax not work reliably over VoIP?
Fax tones are sensitive to packet loss, jitter and codec conversion. T.38 support or an alternative digital document service may be required.