TP-LINK Archer VR900v (v1.0)

Overview
Note: This model is not the VR900, but the VR900v. Both differ quite substancially in both hardware and pricing. Be careful not to mix up "VR900v (v1.0)" and "VR900 (v1.0)"!
 * TP-LINK Archer VR900v on OpenWrt wiki

Specifications

 * The device runs on 2 entirely different SoCs:

CPU:
 * Broadcom BCM4709 (2x 1GHz ARM Cortex-A9) with RAM 128MB and flash 16MB.
 * Broadcom BCM63168 (2x 400MHz MIPS) with RAM 64MB and flash 8MB.

Flash:
 * Spansion S25FL128SAGMFI00 16MB (FL128SAIF00, 439QQ0009 A, SPANSION)
 * Winbond W25Q64FVSSIG 8MB (Winbind, 25Q64FVSIG, 1532)
 * Winbond W25Q80BVSSIG 1MB (Winbond, 25Q80BVSIG, 1444) (DECT)

RAM:
 * SK hynix H5TQ1G63EFR-PBC 128MB (H5TQ1G63EFR, PBC 444V, NWLC2479XH3)
 * Zentel A3R12E40CBF-8E 64MB (A3R12E40CBF, -8E, 527ZENV6, 57025694G-F)


 * For wired ethernet connectivity, the integrated NICs of the BCM4709 are used.
 * That SoC supposedly also features some hardware offloading capabilities
 * as well as hardware accelerated routing.


 * Wi-fi is provided by 2 BCM4360 with an unknown number of antennas.
 * The device has 3 external RP-SMA connectors for wifi, yet the exact
 * wiring/mapping is unknown.

(root@localhost.localdomain) (gcc version 4.6.2 (Buildroot 2011.11))
 * 1) 1 SMP PREEMPT Mon Aug 24 10:08:45 HKT 2015;unknown OS on BCM4709

Serial
The device has at least 2, possibly 3 serial interfaces
 * on the unpopulated 4 pin headers J4, J7 and J8.


 * J4 (unpopulated 3.3V TTL, RX-TX-GND-VCC, 115200,8,N,1)
 * J7 (unpopulated, 3.3V TTL, ?-?-GND-VCC)
 * J8 (unpopulated, 3.3V TTL, RX-TX-GND-VCC, 115200,8,N,1)
 * All operate at 3.3V TTL, J4 and J8 run at 115200,8,N,1,
 * whilst the exact function of J7 is yet unknown.
 * The pinout of all headers is RX-TX-GND-VCC, whilst the exact
 * function of the RX and TX pins on J7 is yet to be found.
 * At least on my board, it was virtually impossible to solder the GND pins
 * on all 3 headers (the other pins could be soldered without any problem).
 * You probably need to brass-brush them prior to soldering (do not brush
 * them after soldering or you will spread fine-ground solder over the PCB,
 * causing possible shortages!).

VoIP / DECT

 * 2 separate VoIP ports are offered through which POTS telephones can be used for VoIP
 * telephony. Both ports feature a German TAE socket and a classical RJ11 socket.
 * I have not tested if you can connect 2 phones simultanously to the same VoIP port.


 * DECT is provided by a DSP DCX81 with a small separated antenna PCB which is integrated
 * into the router's plastic case and is not visible or accessible from the outside.