Cisco Aironet 1800i: Hardware Detail

Cisco Aironet 1800i is a cute little device that is just a little smaller than my hand. They are light in weight, not very hot (not a good replacement of the old 3502i model if you also have a cat around your home) and require less power to operate. I recently got one 1800i in my room, so I’d like to write a little about this model since it is so different from the old PowerPC-based ones.

Networking Specs

Compiled from Cisco Aironet 1800i Access Point Getting Started Guide:

  • Indoors deployment only
  • Embedded two 2.4G + 5.8G dual-band antennas (omnidirectional, [email protected], [email protected])
  • 2.4G: 2SS SU-MIMO
  • 5.8G: 2SS MU-MIMO (802.11ac Wave 2, a.k.a. Wi-Fi 5)
  • One 1Gbps Ethernet uplink
  • Powered by either PoE (802.3af/at) or MicroUSB (5V 1.5A)
  • CAPWAP (Thin) mode only, no Autonomous (Fat) capability (reads: must be used with a controller)
  • Does NOT support wireless mesh
  • Does NOT support Bluetooth beacon

Note that the description of LED patterns in the Getting Started Guide is wrong.

There is an Aironet 1800s model which is based on the same hardware but can only act as a wireless environment sensor/monitor and cannot be used as an AP. The 1800s require a cloud subscription to work properly. Whether the 1800s can cross-flash a 1800i’s firmware is unknown. Considering that 1800i is not even listed in the 1800 series portfolio, I guess it is a last-minute decision to rebrand/reuse the 1800s’ hardware and make a low-end AP out of it.

Hardware Specs

  • SoC: Qualcomm IPQ4019 (Quad-core Cortex A7 @717MHz)
  • Memory: SKhynix 512MiB
  • Storage: Macronix MX25L3205D 4MiB SPI Flash
  • Storage: Spansion (Cypress Semiconductor) S34ML01G200TF100 16MiB NAND
  • Ethernet PHY: Qualcomm Atheros AR8035
  • 2.4G RF Frontend: Skyworks SKY85325-11
  • 5.8G RF Frontend: Skyworks SKY85717-21
  • Bluetooth: TI CC2640 (not used)

The hardware is essentially 2 pieces, one main body with the SoC, SKU AIR-AP1800I-x-K9 (x is your country code); one extension module with the Ethernet port and the power conversion things, SKU AIR-MOD-POE . They can be detached without tool (the mechanical connection is very firm).

The PoE module (left) and the main body (right)

The two modules are connected with a non-standard USB C port and two insert detection pins. (Details below.)

For Aironet 1800s, there are other extension modules available, namely AIR-MOD-USB-xx and AIR-MOD-AC.

PoE Module

The PoE Module accepts an 1Gbps Ethernet connection with 802.3af/at or MicroUSB 5V input, and transfers power and data to the main module.

You can charge a 3rd party device on the module with PoE (5V passive power only, no support for any quick charge protocols so the 3rd party device may limit itself to 0.5A), but it is not a USB to Ethernet adapter (USB C data pins are used to connect Ethernet PHY and MAC) so you cannot use the module as a USB device on any 3rd party USB host. (WARNING: plugging any USB host/device onto that module might damage both of them; although this does not happen in my experiment, I’m not responsible for any damage to your devices.)

2 Philips screws hold its case. After removing them, the PCB can be easily revealed. Please be careful not to bend the insert detection terminals.

The insert detection terminals are wired on the PoE module; they touch one of the metal heatsink plates on the other module when inserted.

Main Body

The main body contains the SoC and all wireless components. Two Philips screws hold the back cover. On the back of the PCB resides the serial port, the reset button, the SPI flash, two coaxial antenna connectors for Wi-Fi and one smaller unconnected coaxial connector for Bluetooth. Other major components are hidden under the big metal shield.

Disconnect the two antennas, then use the ring structure on the metal heatsink as a fulcrum to raise the board. On the front side of the board we have two more metal shields and a tri-color LED.

Side-view of the PCB sandwich:

When assembling the main module, first put the PCB into the case, then insert the PoE module before screwing the back cover. Otherwise the USB C port might not align.

Serial Port

The serial port is one with an absolute propriety (TM) connector. Cisco sells the AIR-CONSADPT= to convert it to a traditional RJ45-like RS232-level port to achieve compatibility with the good old USB RS232 serial cable, but this converter is not globally available and is rarely seen on second hand markets. Luckily, you can make yourself a serial cable out of simple parts. What you need is:

  • A JST GH (1.25mm/0.049in) connector with breakout cables (it might not fit well in the port, but most of GH connectors on the market can work with some additional force)
  • A 3.3V (TTL level, UART) serial to USB adapter board
  • Some 2.54mm female wires that connects to the serial to USB adapter

Connecter definition (left to right, the Ethernet port towards the left):

  1. VCC, 3.3V (for powering the Cisco adapter; do not connect it)
  2. RX
  3. TX
  4. GND

Connect the AP and the USB serial converter (you might need some soldering), GND to GND, RX to TX and TX to RX. If your USB serial converter have voltage/level selection jumper or switch, select 3.3V. You should end up with something like this (please do proper isolation between naked wires, don’t be like me):

Cisco Aironet 1800i connected to a CH552 serial-to-USB adapter

Plug the USB serial converted to your computer. Set your serial port software to 9600,8N1, or:

  • Baud rate: 9600
  • Parity: none
  • Stop bit: 1
  • Data bits: 8
  • Flow control: XON/XOFF or none

and profit. The default username and password are both Cisco.

Factory image (version boot log, if anyone is interested:


Leave a Reply

Your email address will not be published. Required fields are marked *