Linksys WRT54G series

The devices have two removable antennas connected through Reverse Polarity TNC connectors.

As a cost-cutting measure, as well as to satisfy FCC rules that prohibit fitting external antennas with higher gain, the design of the latest version of the WRT54G no longer has detachable antennas or TNC connectors.

Instead, version 8 routers simply route thin wires into antenna 'shells' eliminating the connector.

As a result, Linksys HGA7T and similar external antennas are no longer compatible with this model.

Note: some of the routers have BCM4702 CPU[4] The WRT54GS is nearly identical to the WRT54G except for additional RAM, flash memory, and SpeedBooster software.

This allows for greater flexibility of configurations and scripting, enabling this small router to both load-balance multiple ADSL lines (multi-homed) or to be run as a hardware layer-2 load balancer (with appropriate third party firmware).

[citation needed] WRT54GP2 has 1 or 2 antennas, and a built-in analog telephony adapter (ATA) with 2 phone lines, but only 3 network ports.

The "C" in the router number stands for compact, as the unit measures 4" by 4" by 1" with an internal antenna.

The internal hardware is based on a Marvell ARM914 ("Libertas") reference design which is probably identical to the SerComm IP806SM, Xterasys XR-2407G, Abocom ARM914, Hawking HWGR54 Revision M, and the Airlink 101 AR315W.

For example, Telus Mobility (CANADA) uses the Sierra Wireless Aircard 595, which is supported by this router, but because it is from Telus Mobility and not from Sprint (USA), it will never load the card into the router to make it operational.

It allows calls to be made via T-Mobile's GSM network or via Wi-Fi Unlicensed Mobile Access (UMA), using the same telephone and phone number (a special dual-mode phone designed for the service is required e.g. BlackBerry Pearl 8120).

It works with Rogers' Talkspot UMA service, which allows calls to be made via Rogers' cellular network or via Wi-Fi Unlicensed Mobile Access (UMA), using the same telephone and phone number.

[38] After Linksys was obliged[39][40] to release source code of the WRT54G's firmware under terms of the GNU General Public License,[41] there have been many third party projects enhancing that code as well as some entirely new projects using the hardware in these devices.

The amount of flash memory in the version 5 devices has been reduced to 2 MB, too small for current Linux-based third-party firmware.

(See table above for information on identifying the version based on the serial number printed on the bottom of the unit, and on the outside of the shrink-wrapped retail box.)

[42][43] An easier method not requiring any disassembly of the device has since been devised for flashing v5-v8 to DD-WRT.

After testing for proper functionality of the modified unit, third-party firmware can be flashed using the JTAG cable and a suitable image file.

With the Attitude Adjustment (12.09)[46] release of OpenWrt, all WRT54G hardware versions with 16 MB of RAM are no longer supported, and older Backfire (10.03)[47] is recommended instead.

Issues came from dropping support for the legacy Broadcom target brcm-2.4, making lower end devices run out of memory easily.