Grandstream HT812 V2 2-Port ATA IP Telephone Adaptor

The Grandstream HT812 V2 is the small analogue adaptor most sites end up with: two FXS ports, so two analogue phones, fax machines, door phones or alarm diallers keep working on a VoIP system. It is the cheapest honest answer to "we are moving to SIP but this one device has to stay".

Two SIP profiles mean the two ports can belong to different providers or different systems — a fax on one account and a lift phone on another, for instance — rather than being tied together.

It also has two Gigabit ports and a built-in NAT router, so it can sit inline at a small site instead of behind one. The router itself handles traffic at up to 100 Mbps; the Gigabit ports mean nothing else on the link is throttled.

Key features

• 2 FXS ports — two independent analogue devices
• 2 SIP profiles — the ports can use different providers or systems
• 2 Gigabit Ethernet ports with a built-in NAT router
• T.38 fax relay to 14.4 kbps, with automatic fallback to G.711
• Wide codec support — G.711, G.723.1, G.726, G.729A/B, iLBC and Opus
• HD voice on the analogue ports
• TLS and SRTP — signalling and media encryption
• Automated provisioning — deploy without touching each unit
• Compact and fanless — fits behind a desk or in a small cabinet

Works with

• HT814 V2 — four FXS ports
• HT818 — eight FXS ports
• HT813 — one FXS and one FXO, for a PSTN fallback line
• PSU for HT812 / HT813 — spare or replacement power supply
• GXW4216 V2 — 16 ports, when the count grows
• Grandstream UCM IP PBX range — register the ports to an on-site PBX

Frequently asked questions

Will my existing analogue phone just work?

Yes. An FXS port supplies line voltage, dial tone and ring current exactly as an analogue exchange line does, so the handset behaves normally.

Do fax machines actually work over this?

It supports T.38 fax relay, which carries the fax as data instead of pushing fax tones through a voice codec, and falls back to G.711 if T.38 is unavailable. Your provider or PBX also needs to support T.38 at the other end.

What is the difference between the HT812 and the HT812 V2?

V2 is the current hardware revision of the same product — two FXS ports, two SIP profiles, Gigabit NAT router. If you are buying now, buy the V2.

Can the two ports be on different providers?

Yes — that is what the two SIP profiles are for. A common setup is a fax on one carrier and a lift or alarm line on another.

Does it need to be my router?

No. The NAT router is there if you want it inline at a small site, but it works perfectly well plugged into an existing network as an ordinary device.

2, 4 or 8 ports?

One port per analogue device. Count the handsets, faxes, lift phones and alarm diallers first — it is normal to find more than expected. Beyond eight, move up to a GXW gateway.

Not sure how many ports you need? Call 0333 242 1314 or email sales@clisecure.com and tell us what the analogue devices are.