I’ve had a Cisco LinkSys E1000 router/Access Point in my collection for some time now. I’ve been meaning to use it as my router and Access Point, instead of the Comcast cable modem, at home, so I can get a lot more detail about the network traffic between all of the hosts in my house and the Internet. I intend to install dd-wrt on the E1000 before I actually start using it.

Since I have been playing with many LinkSys WRT routers over the years and since I knew that some of them had a serial port on the circuit board, I wanted to be able to use the serial port on this E1000, before I actually started using it. In this article I’ll describe the few simple steps required to be able to use that serial port (which the E1000 does indeed have).

My E1000 is a version 2.1 device, as printed on the label on the underside of the case. Judging by some information I found in other people’s ‘blogs, this circuit board is different from the version 1.0 board.

The serial port is provided via a row of solder points which are labeled DJ2. There are a total of five solder points (actually, holes through the board) and they are:

Ground

Unknown

Transmit

Receive

Voltage

If you open the case and orient the board such that the word “CISCO” is properly oriented and toward the bottom of the board, the connections are Ground on the left and Voltage on the right. The board uses 3.3 Volt signaling, so it’s not actually an RS-232C serial port. You’ll need a way to convert from 3.3 Volts to 5 Volts if you want to use a proper RS232C serial device to connect to the E1000 serial console. I used a Sparkfun FTDI converter.

Once you’ve established the physical connections, to Transmit, Receive and Ground, the data rate is 115,200 and the protocol is 8 data bits, no parity and one stop bit. It is an ASCII conversation and you’ll be given a BusyBox prompt when you connect. You many have to send one NewLine character to get a prompt from BusyBox.

Next for me is to install dd-wrt on this E1000.

 

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