TP-Link TL-MR3420 is an beautiful 3G/4G Wireless N Router which allows sharing of high-speed 3G/4G CDMA/GSM data over WiFi and LAN, the router features an comprehensive list of supported USB data dongles and is plug-n-play compatible with majority of them. However, despite being shown supported the BSNL ZTE AC8700 EVDO modem refused to connect, even after using the latest official firmware from TP-Link's website it refused to connect while the modem get successfully identified. Finally, after getting the BETA firmware directly from TP-Link India's support desk it worked. Direct download link and process to flash this working beta firmware "mr3420v2_en_3_13_27_up_boot(121212)Beta.bin" is posted below.

EVDO is the 3G internet access technology for CDMA platform, the Evolution-Data Optimized(EVDO) technology offers mobile broadband speeds upto 3.1 Mbit/s.

I have been providing internet access to my Raspberry Pi via an TP-Link WiFi 3G Router, however we can directly connect a GSM/EVDO 3G dongle to any Linux computer and make it act like a WiFi access point using Linux utilities like WICD Network Manager. Configuring a EVDO modem to work on Linux can get a bit tricky, here is a simple to follow howto guide on setting things up.