This is a closer look at two hardware versions of the Grandstream GXP16xx series phone.

Both phones shown above are from the GX16xx series and look cosmetically the same on the outside. On the left is a GXP1620 HW v1.4B; on the right is the GXP1625 HW v2.5A. The GXP1625 models add a few components to allow Power over Ethernet (omitted with the GXP1620), but this is not the primary difference between the phones shown.

The HW v1.4B uses a DSP Group DVF99185 whereas the HW V2.5A uses a DSP Group DVF97187. As you can see in the table below, the former is a "Low-End IP-Phone" and the latter is an "Ultra-Low-End IP-Phone". Both designs incorporate 16MBytes of NOR flash and 32MBytes of SDRAM.

Despite the different CPUs, the firmware update images are the same; the only difference in the firmware is the uboot code.

As with the GXP21xx, cheap Chinese labor seems to cause the designers to not bother with thinking of ways to reduce touch labor.

In no particular order, here are some of the changes between HW v1.4B and HW v2.5A:

* The latter's DVF97187 comes in a QFN package, and this also seems to have accompanied with some more creative curved PCB traces in portions rather than the Manhattan-style routing of the former.

* For whatever reason, they've not only redesigned the main PCB, but relocated the connector to the keypad board (which then forced that board to be redesigned as well).

* Although the PCB has changed shape and location, the ribbon cable to the LCD display is still the same length suited to the previous design.

* The new debug connector is missing JTAG/SWD.

* The PoE rectifiers were moved to the top of the board, leaving only small passives on the back of the board.

GXP162x v1.4BGXP162x v2.5A

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