Andrew Mercer
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Do these steps once, after unboxing or a factory reset, before adding a provider.

Where things live in the web UI

The HT812 splits SIP configuration across two kinds of pages:

  • Profile 1 / Profile 2: server-side settings: SIP server, outbound proxy, NAT, codecs, dial plan, registration timers. Several ports can share one profile.
  • FXS Ports: per-line settings: which profile each port uses, plus that line's SIP User ID, Authenticate ID, password, and display name.

Typical setup: Profile 1 holds your provider's server settings, and Port 1 holds the account credentials and uses Profile 1. Port 2 can share Profile 1 (a second account at the same provider) or use Profile 2 (a different provider).

After changing settings, click Apply (some firmware also has a separate Save step). Reboot if registration doesn't update.

1. Secure the device

  • Change the admin password (Advanced Settings).
  • Update the firmware (Maintenance → Upgrade).
  • Leave web access from the WAN side disabled unless you need it, and never expose the web UI or SIP ports to the internet with port forwarding.

2. Choose a network mode

The HT812 is a router by default: NET1 is WAN, NET2 is LAN.

  • Simplest: switch to bridge mode so the HT812 gets an address from your home router like any other device and there is only one NAT layer.
  • Router mode is fine too. Just remember the web UI is reached from the NET2 side unless WAN access is enabled.

Give the device a DHCP reservation on your router so its address doesn't change.

3. Time zone

Set the time zone (for Ontario, Eastern Time with automatic DST) and NTP server under the basic/advanced settings. This affects call logs and caller ID timestamps.

4. Pulse dialing (rotary phones)

The HT812 supports pulse dialing, but it must be enabled for the port or profile used by the rotary phone. Look for a setting named like Enable Pulse Dialing (set to Yes) and, if present, a pulse dialing standard (use the general/North American option).

If a rotary phone gets dial tone but calls don't go through or digits are wrong:

  • Confirm pulse dialing is enabled on the right profile/port.
  • Clean and adjust the dial. Wrong digits are usually a dial running fast or slow, not a configuration problem.
  • Remember that a rotary phone can never send * or #. For voicemail menus and automated systems, add a pulse-to-tone converter (see Using a rotary phone today).

5. Dial plan

The dial plan tells the ATA when a number is complete, so it sends the call immediately instead of waiting for a timeout. That matters a lot with a rotary phone. Grandstream uses this syntax:

  • x = any digit, [2-9] = digit range, + = one or more of the previous, | separates rules, all wrapped in { }.

A North American plan with 10-digit local dialing (required in most of Ontario):

{ [2-9]xx[2-9]xxxxxx | 1[2-9]xx[2-9]xxxxxx | 011x+ | 911 | [2-9]11 | *x+ }
Rule Matches
[2-9]xx[2-9]xxxxxx 10-digit local/North American number
1[2-9]xx[2-9]xxxxxx 1 + 10 digits (long distance)
011x+ International (sent after the inter-digit timeout)
911 Emergency
[2-9]11 211, 311, 411, 511, 611, 811 service codes
*x+ Provider feature codes (Touch-Tone phones only)

Add any provider-specific short codes (such as a voicemail or echo-test number) as extra rules. Keep the 911 rule on every profile.

6. NAT and keep-alive

Most "phone registers but has no audio" or "incoming calls stop after a while" problems are NAT problems.

In the profile settings:

  • NAT Traversal: start with Keep-Alive (or No if your provider recommends it, and turn on keep-alive messages instead). Avoid STUN unless you've configured a STUN server.
  • Register Expiration: a few minutes (for example 5) rather than the default of an hour, so the NAT mapping on your router stays open.
  • Unregister On Reboot: Yes, so stale registrations are cleared.

On your home router, turn off SIP ALG if it has one. SIP ALG rewrites SIP packets and is a very common cause of one-way audio and missed incoming calls.

7. Ringing

  • System Ring Cadence defaults to c=2000/4000 (2 s on, 4 s off), the North American standard, which suits a vintage bell.
  • The HT812 drives 3 REN per port: enough for one mechanical-bell phone, usually two.

8. Power

An ATA and router stop working during a power outage. If the phone needs to work when the power is out, put the modem, router and HT812 on a UPS.

Next

Add a provider: VoIP.ms, Freephoneline, Callcentric, or a self-hosted PBX.

Sources