Perhaps relying on the processor’s integrated memory, the manufacturer installed only 16MB of memory into the router. This is the typical amount for a regular SOHO router, yet it seems somewhat small for this particular model. Physically, it is an A2S28D40CTP chip of DDR SDRAM manufactured by PSC.
The router’s OS is stored in a Macronix 25L3205 flash memory chip. This chip has a serial interface and a capacity of 4MB. The firmware image is about 1MB large, so there is an opportunity to make substantial additions to the router’s standard firmware.
The DIR-655 employs a VSC7385 Gigabit Ethernet switch made by VITESSE. This SparX series chip is recommended for use in high-performance SOHO solutions. The chip offers 5 ports, has a 112KB frame buffer, supports IPv4 and IPv6 networks (with Jumbo Frames), and features integrated tools for QoS and other services. Having an integrated processor, it can even work as a router in its own right, but this capability is not utilized in the DIR-655.
The WLAN module resides on a separate card that is attached to the main PCB via a miniPCI bus. Here, we’ve got an AR5008-3NG version of the xspaN AR5008 chipset from Atheros. It employs an AR2133 RF module and an AR5416 MAC controller.
Winding up this section, I want to note two more things in the router’s electronics. First, there is an empty seat for a console connector near the processor. And second, I couldn’t find out the purpose of the button soldered together with an indicator near the right edge of the main PCB. It will probably enable a quick-setup mode or something in future revisions of the router.