Tag Archives: dlink

D-Link DSL-2320B with Sonic Fusion Internet

If you’re here just for the settings, you need not go any further than the first image below:

These are the settings that work with Sonic Fusion Internet in San Jose, California.

And now, step-by-step. There are definitely other ways to configure the modem, including over USB, and using a Wizard, but this is how I did it. New out of the box, I powered up the modem and connected an ethernet cable between it and my laptop. I pointed my browser at, and logged in with default username Admin, password Admin.

I went to WAN on the left sidebar. On the page that came up, I clicked Add.

Notice that no services are listed on this page.
The next page showed VPI=0, VCI=35, which is correct for my ISP. Next.
Default was PPP. Chose Bridging. Next.
Leave the box checked for Enable. Leave service name alone, it doesn’t matter, anyway. Next.
A summary of settings was shown. Apply.
The service is shown now, but I still needed to click Finish. The modem rebooted itself. When it came up again, DHCP was disabled, so I couldn’t log in. But when connected to the phone line, it worked perfectly.

And now, the months-long saga of the modem issue. Move along, nothing to see here.

We have had Sonic Fusion (ADSL2+) as our ISP for over 10 years. I liked that they gave me a static IP upon request, as I host pididu.com on a small server in our bedroom. (We also have Xfinity in the house, but that’s irrelevant to this article.) A few months ago, on random days, the speed would drop to 1 Mbps at times, and stay there. When that happened, a power cycle of the modem would bring the speed back up to the normal of about 20 Mbps. I doubted that wiring could be at fault, because a technician came over a few years ago and redid the connections for all our phone wiring. So naturally, I suspected the modem.

For a while, I substituted the Actiontec GT-701D below, which I had kept around as a spare. However, that modem only supported speeds of up to about 10 Mbps (ADSL2, G.992.3). Although the ActionTec seemed reliable, I decided it was better to simply use the Comtrend CT-5072T and power cycle it on the rare days when the issue occurred.

ActionTec GT-701D. I got it for $10 on craigslist a decade ago.

Clearly, I needed a new modem which would work at full ADSL2+ speed. I found one on eBay, $10 with free shipping. It was a Speedstream 5100.

Despite the listing saying that this modem supported up to 24 Mbps, it was actually ADSL2, not ADSL2+. Error in listing. Not worth returning.

The next modem I got was off craigslist again, a Speedstream 4100B, which I took great pains to validate that it was, indeed G.992.5 (ADSL2+). It turned out to be sold by someone I knew. I couldn’t get it to sync to DSL. So it was broken. But since it was a friend, I didn’t bother him for a refund.

Enough messing around. I decided to get another Comtrend CT-5072T, the exact model that had worked so well all those years. There was one that was advertised as Never Used on eBay for about $30.

This is the Comtrend modem from eBay. I was unable to log in with the usual passwords, so contacted the seller to see if she at least knew where the modem had come from. She immediately refunded all my money, including tax and shipping. I guess that’s how a seller gets a 100% positive feedback rating, but I still was without a solution.

One possible positive about the Comtrend modem that I got was that it came with a power supply. I substituted the new power supply for the old one on the existing modem, and did not see the speed throttling problem again. Maybe that was the issue all along?

I was beginning to realize how passe DSL was. It was HARD to find a DSL modem only anywhere. A few modem / wifi router combos were available, but those were not what I needed, since I had an excellent router, already. I also realized that these old modems were pricey, likely because they are not made, anymore. I was able to find a D-Link DSL-2320B for around $60 on eBay, New in Box. Surely, that would work. An aftermarket product like that would have to be configurable to work on any ISP. I checked the specs on D-Link’s site, and indeed, that was an ADSL2+ device. I ordered it. Even if the power supply actually fixed the Comtrend failure, I still needed a backup.

You can tell that this is old hardware just by looking at the box. There’s no mention of XP SP3, let alone Windows 7.
Here is the D-Link in service in our attic. Just to the left is the old Comtrend modem, and to the left of that, the Netgear RAX-35 router.
There is one other possible suspect. This power outlet in the attic is arc-fault protected. Yes, arc-fault, not just ground-fault. At some time after the last throttling failure, this breaker tripped. Maybe it was marginal, or injecting some kind of noise into the modem on occasion? There were no failures after resetting this outlet, but then again, the power supply on the Comtrend modem had also been changed, so either of those could have been the cause. Or neither.