DIR-620 rev D1

The D-Link DIR-620 rev D1 router has 300mbps WiFi, 4 100mbps ETH-ports and 0 USB-ports. It also supports custom firmwares like: dd-wrt, OpenWrt

Quick links:
Default password/Login
Flashing Custom Firmwares

DIR-620 rev D1 router specifications (specs)

System specs
CPU: 400 MHz
RAM: 32 MiB
Flash: 8 MiB
Custom firmwares: dd-wrt, OpenWrt

Connectivity
WiFi: 300mbps (bgn)
WiFi bands: n/a
WiFi throughput: n/a
WAN: 1 x 100mbps port
ETH: 4 x 100mbps ports
USB-ports: 0

Hard reset instructions for D-Link DIR-620 rev D1

If your DIR-620 rev D1 router is not working as it should, dropping connections or not being responsive, you should first do a reset of the router to see if the problems persist. Other scenarios where you might want to reset your router is if you've forgotten the password or misconfigured it and can't get access anymore.
Your can reset your D-Link DIR-620 rev D1 in the following way(s):

With the reset button

Locate the reset button on the back off the router
While the unit is powered on, press the reset button with a sharp object (e.g. paperclip)
Hold the button pressed for 10 seconds, then release.
The unit will reboot by itself and once the WLAN light stops blinking the factory reset is done.
You can now setup your router again through the user interface

The 30-30-30 reset

If the above instructions don't work you can always try the 30-30-30 reset as follows:

When router is powered on, press the reset button and hold for 30 seconds. (Use a paper clip or something sharp)
While holding the reset button pressed, unplug the power of the router and hold the reset button for 30 seconds
While still holding the reset button down, turn on the power to the unit again and hold for another 30 seconds.

This process usually works for resetting any router to it's factory setting.

Note: It is worth reading more about how to reset routers with the 30 30 30 reset and what the risks and considerations are when resetting your router this way, instead of just rebooting it.

Default factory settings for D-Link DIR-620 rev D1

If you have performed a reset of your DIR-620 rev D1 device or not changed the defaults, you should be able to access it with the following settings:

Default username: admin D-Link router default password list
Default password: admin
Default subnet mask: 255.255.255.0

Note: If you are using the default settings you should change them to increase security and prevent unathorized access to your network.

DIR-620 rev D1 Firmwares

Staying up to date with the latest firmware is a good idea to keep your router even more secure from various security flaws.
If you want to squeeze a little bit of extra functionality out of your router, consider flashing an open-source firmware like dd-wrt, openWRT or LEDE. Flashing a custom ROM can greatly increase the stability and functionality of your old router.
Following are the firmwares that we have identified existing for the D-Link DIR-620 rev D1:

Flashing dd-wrt on the D-Link DIR-620 rev D1

Instructions on how to flash dd-wrt onto your D-Link DIR-620 rev D1 can be found on the dd-wrt wiki
Note: Always make sure to read the wiki and howtos of dd-wrt before doing any flashing.

Flashing OpenWrt on the D-Link DIR-620 rev D1

The D-Link DIR-620 rev D1 is supported by OpenWrt according to their Table of Hardware. So flashing OpenWrt onto it should be quite straigthforward.
To get started with the flashing, head over to the OpenWrt instructions for DIR-620 rev D1 and they'll take it from there.
Note: Flashing custom firmwares is always on you're on own risk. Make sure to read OpenWrt's wikis to understand the risks and how to proceed if something goes wrong.