Over the past several months my ADSL modem, a Billion 7402R2, has developed a habit of randomly rebooting. This is normally preceeded by a short period (under 1 minute) of unresponsiveness. It might happen several times in one day, followed by 2-3 weeks of uptime. Previously uptimes of 100+ days were normal.

My question is: what could be causing the reboots? Age? The modem (including power supply) is only about 3-4 years old.

Should I be looking at replacing a modem that otherwise does all I ask of it?


Is the firmware up to date? Do you do much torrenting? They often reboot when they overflow the address space which torrents can do. There are a lot of discussions about Billions at Whirlpool which may be able to help/

Billions are pretty tetchy with noisy power. I had a problem with one every time I plugged and external HDD in. It turns out the HDD's power supply generated a lot of electrical noise which upset the modem. I recently replaced it and it was about 3-4 years old.

  • Firmware is up to date, and going back to an older version from when it was stable didn't make a difference. I do torrent, but don't consider myself a heavy user. I'll cut it back and see how it goes. It would be nice if I could monitor the address space usage via snmp.
    – pgs
    Oct 15 '09 at 15:46
  • They often reboot when they overflow the address space which torrents can do. - huh?
    – Ciaran
    Dec 19 '10 at 23:33
  • @Ciaran. Thanks for the downvote. I suggest you do some research on NAT tables and how a large number of connections can affect that. google.com.au/search?q=adsl+modem+roboot+torrents+NAT+table
    – CAD bloke
    Feb 16 '11 at 19:29
  • 1
    The NAT table on that router holds 1500 entries. It is conceivable that seeding a lot of highly-seeded torrents on a few computers could fill that. The size of the NAT table has little or nothing to do with available RAM in the router. I didn't say this was the cause, just a possibility.
    – CAD bloke
    Feb 17 '11 at 2:51

It sounds like your modem is preparing to fail. Hardware can fail after a time and failure would not be unheard of after 3-4 years. The only other thing I can think of is if you are using torrents or otherwise transferring higher volumes of data that your connection can get muddled with by the carrier on purpose. On torrents you should be randomizing the ports it uses and encrypting the traffic (the standard torrent software will do this). That seemed to solve my issues with my carrier. If those don't sound like an issue, I'd look at replacing your modem, making sure the replacement is high quality. Some of the stuff pushed by carriers can be bad.


I normally give an ADSL modem a lifetime of 4 to 5 years.

Normally when I see this kind of issue the basic troubleshooting I'll do is move to a different power outlet and change the power cable. But it usually comes down to a problem with the box itself.

Are you 100% sure the modem is powering itself off? Does it get hot when left on?

Intermittent connections can be caused by a line fault, exchange fault or internal CPE fault. Just keep an eye on it when its going off. Make sure the power light remains (green, not red, some modems don't have 2 colours) and watch that the DSL light isn't flashing or off. If after 2 weeks when the connection starts to get intermittent, the DSL is intermittent it means you've got an intermittent sync.

To be honest though this kind of problem, where the connection will be perfect for 2 weeks and then go bad, you're looking at a heat problem and your modem will need to be replaced.

In my experience, the tell tale symptom is the heat coming from the box so check that when it starts to go bad. It could mean solder melting and settling when cooled again.

My main suggestion to you: Find out whether its actually rebooting or if its losing sync (DSL light going off/flashing)

Edit: If you do plan on replacing the modem, ring your ISP first. They'll normally do it for free or quite cheap. Otherwise get a better brand modem.

  • A solid-state device wears out or changes its thermal properties? True that capacitors wear out but I downvoted you because your answer is even lamer than mine. If its full of dust then just pull the lid off & clean it out.
    – CAD bloke
    Feb 16 '11 at 19:31

I had the same experience. It was because my ADSL modem only supported ADSL 1, but not ADSL 2+. I was told that after time, such a modem gets "worn out" when the carrier supports ADSL 2+. Replacing the modem was the only choice.

  • I never imagined that happening. This is, however, an ADSL 2+ modem connected to a 2+ exchange.
    – pgs
    Jul 15 '09 at 10:31

After several months, the modem stopped rebooting, and became stable enough to have an uptime of over 12 months. I guess the problem was noisy power.

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