What evidence, data, (whatever you want to call it) do you
have that suggests it times out?
The log, I'd imagine. The D-Link 624 routers keep a log of events
like resets, ISP connects, connection time outs, wireless connections,
etc. You just need to go into its configuration menu to see what it's
been doing for the last little while.
If the DSLreports forum is any indication, it's a fairly common issue
with the 624 routers (I own one a revision C1 myself). It's kind of a
normal thing to have a few time-out events from time to time. A DSL
connection isn't supposed to be always connected 24-7, so the ISP will
probably shut you down if you've been connected for long enough. You
can usually still log back in right away. The sort of periodic
"thrashing" that the 624 exhibits from time to time where it just
keeps timing out and logging in repeatedly every few minutes (or
seconds) isn't acceptable, but if it times out on you every 2 or more
hours, that's nothing to get excited about. The thrashing seems to
happen more often when the wireless transmission mode is enabled (ie.
using it as a wireless access point), but it still occurs even if you
disable all wireless features and use it as a regular DSL router.
Assuming all your settings are correct for your ISP, first try
changing the connect mode to "Connect-on Demand". Log onto the router
and you'll find this in the router's config under HOME > WAN > near
the bottom of the page.
This mode has proven thrash a bit less than the "always on" mode when
using firmwares later than 2.40. The firmwares older than that tended
to do the time-out thrash a bit more than the later ones. That leads
to the next suggestion: Update the firmware. D-Link has been working
to tweak the behavior of the routers to be a bit more ISP friendly and
time out less.
Just remember (IMPORTANT), before you do that: Write down ALL your
router config settings before you do it. The firmware updates will do
a hard reset, and sometimes (not sure if it's intentional) it wipes
the router's memory, including all your settings. If you find you
can't access the net, or your regular password for the router doesn't
work, that's what happened. You have to go back in and change all
your settings back. The default username is "admin" and the default
password is just left blank, if you can't find your manual (freaked
out the first time this happened to me).