Add Adtran SDX 611 hardware specifications and teardown photos (#448)

- Add chipset (Realtek RTL9601D), flash (Winbond W25Q128JVSQ 16MB), optics (U&T UTG24P05) to hardware specs table
- Add serial console info (GND/TX/RX headers pre-soldered, 115200 8-N-1)
- Add board revision: Adtran-611-V2 REV1.0
- Add disassembly instructions (screws under rubber feet, snap-fit rear cover)
- Add chip identification table
- Add teardown and chip macro photographs

Co-authored-by: Jaylouisw <jaylouisw@users.noreply.github.com>

Author: Jaylouisw

_ont/ont-adtran-sdx-611.md

@@ -7,22 +7,59 @@ parent: Adtran
 
 # Hardware Specifications
 
-|              |         |
-| ------------ | ------- |
-| Vendor/Brand | Adtran  |
-| Model        | SDX 611 |
-| Chipset      |         |
-| Flash        |         |
-| RAM          |         |
-| System       |         |
-| 2.5GbaseT    | No      |
-| Optics       | SC/APC  |
-| IP address   |         |
-| Web Gui      |         |
-| SSH          |         |
-| Telnet       |         |
-| Serial       |         |
-| Form Factor  | ONT     |
+|                 |                                          |
+| --------------- | ---------------------------------------- |
+| Vendor/Brand    | Adtran                                   |
+| Model           | SDX 611 (Adtran-611-V2 REV1.0)           |
+| Chipset         | Realtek RTL9601D                         |
+| Flash           | 16 MB (Winbond W25Q128JVSQ)              |
+| RAM             |                                          |
+| System          |                                          |
+| Optics          | SC/APC (U&T UTG24P05)                    |
+| 2.5GbaseT       | No                                       |
+| IP address      |                                          |
+| Web Gui         |                                          |
+| SSH             |                                          |
+| Telnet          |                                          |
+| Serial          | ✅                                       |
+| Serial baud     | 115200                                   |
+| Serial encoding | 8-N-1                                    |
+| Form Factor     | ONT                                      |
+
+## Disassembly
+
+1. Remove the two screws hidden under the rubber feet on the back of the unit
+2. Use a plastic pry tool to separate the rear cover, as it is held in place by a snap fit
+
+{% include alert.html content="Be careful when prying the rear cover off, the snap fit clips can break easily." alert="Note" icon="svg-warning" color="yellow" %}
+
+{% include image.html file="sdx611-teardown-1.jpg" alt="Adtran SDX 611 Teardown" caption="Adtran SDX 611: Teardown" %}
+{% include image.html file="sdx611-teardown-2.jpg" alt="Adtran SDX 611 Board" caption="Adtran SDX 611: Board" %}
+{% include image.html file="sdx611-board-rev.jpg" alt="Adtran SDX 611 Board Revision" caption="Adtran SDX 611: Board revision (Adtran-611-V2 REV1.0)" %}
+
+## Serial
+
+The board has GND, TX and RX headers already soldered. A USB UART adapter such as a CH340G can be used to access the serial console.
+
+| USB TTL(UART) Adapter | Board header |
+| --------------------- | ------------ |
+| GND                   | GND          |
+| TX                    | RX           |
+| RX                    | TX           |
+
+{% include alert.html content="Some USB TTL adapters label TX and RX pins the other way around: try to swap them if the connection doesn't work." alert="Note" icon="svg-warning" color="yellow" %}
+
+## Chip identification
+
+| Chip                   | Function           |
+| ---------------------- | ------------------ |
+| Realtek RTL9601D       | GPON SoC           |
+| U&T UTG24P05           | Optical transceiver (BOSA) |
+| Winbond W25Q128JVSQ    | 128Mbit (16MB) SPI NOR Flash |
+
+{% include image.html file="sdx611-rtl9601d.jpg" alt="Realtek RTL9601D" caption="Realtek RTL9601D GPON SoC" %}
+{% include image.html file="sdx611-utg24p05.jpg" alt="U&T UTG24P05" caption="U&T UTG24P05 Optical Transceiver" %}
+{% include image.html file="sdx611-w25q128jvsq.jpg" alt="Winbond W25Q128JVSQ" caption="Winbond W25Q128JVSQ 16MB SPI NOR Flash" %}
 
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