HT 802 stops and requires cycling power every day


I’m seeing others with similar issues but no resolution.

I have a site that has had an HT802 providing dial tone to two FAX machines for nearly 4 years without issues.
In the past month, the user has had to restart the HT802 each morning to get it to work.

I replaced the HT802 yesterday with a new one. I also moved its network connection from the back of a phone (should be for a PC) and connected it to another wall jack that’s directly patched to the network switch.

I got word this morning that the HT802 had to be restarted again.

I can understand the old one being OLD and needing to be replaced. But having a 2nd one doing the same thing.
When I replaced the unit, I used the NEW power supply that came with the new unit along with a NEW patch cable that also came with the new HT802.

I have opened a ticket with support, but figured I’d also ask here to see if anyone has resolved this on the HT802’s.

Both units have the latest firmware available. I don’t see any BETA versions or any notes referring to this issue on the firmware notes.


So how is the HT setup with regard to the NAT of the site? How does it keep responses flowing to and from the SIP provider such that the firewall does not close?


the PBX and device are on the same LAN infrastructure. The PBX is and the device is

there’s a L3 switch that provides unblocked routing between the two VLAN’s.

The device had been running since 2019 without issues. And the user started complaining that she has started to have to reset it every morning for about 3 weeks now.


Are keep alives enabled? If not, you might give that a shot. Normally, I would not advocate it, but perhaps the lack of data being generated causes the port switch to go green.


which options need to be enabled?

I see something on the Advanced Settings - the Keep Alive Interval is set to 20 seconds.

In the FSX ports, I see:
NAT Traversal = NO - the options are: Keep Alive, STUN, UPnP and VPN

Enable SIP Options/Notify Keep Alive = currently set to NO. the other options are OPTIONS and NOTIFY.
SIP OPTIONS/NOTIFY keep alive interval = 30 seconds
SIP OPTIONS/NOTIFY Keep alive Max Lost = 3


There is no NAT traversal so leave as No.

In the SIP section, enable the keep alive and use Options with a frequency of 30 sec. Max lost at 3 is OK as well.


We ended up replacing it with an HT812. The issue cleared and the user hasn’t had to restart the device since.


Interesting, that perhaps points to a firmware bug in the HT802 software, which is not there in the (slightly different) HT812 software?

Thanks for coming back to update us!