serial port mods

Discussion in 'Modding Forum' started by jagboy, Apr 22, 2005.

  1. jagboy

    jagboy Network Guru Member

  2. berndg

    berndg Network Guru Member

    Linksys WRT54GX serial port mod

    Hi, does anybody know if the serial port mod is also supported by any 3rd party firmware?
  3. XCOM7

    XCOM7 Network Guru Member

    I dont think 3rd party firmware has to support the console mode... unsless you want to console in for config.
    Most of the time you want to console in is when your router is brick or unresponsive to pings.... Thats when you go in to the router and console in.. is called "recovery mode"
  4. littlewhoo

    littlewhoo Network Guru Member

    Re: Linksys WRT54GX serial port mod

    Serial port mods are firmware-independent. This is just a way to get some low-level access to the router.
    But you can't add serial ports to WRT54G v1.0 and v1.1 units.
  5. berndg

    berndg Network Guru Member

    Re: serial port mod

    Cool - i already thought that this should work across several platforms => my (hopefully) last question is: how do i have to configure f.e. hyperterminal in winxp to access my router via the serial port?
  6. davidsonf

    davidsonf Network Guru Member

    Re: Linksys WRT54GX serial port mod

    Serial port mods are only firmware independent to the degree that none of the existing firmware packages available has removed support for using the serial port. It is certainly possible to do that. It is also very possible that some of the firmware packages have in fact accidentally destroyed the ability to use the serial port, simply because I doubt that any of them other than those from Linksys itself are actually being tested with a serial console attached to veryify that it works.
  7. berndg

    berndg Network Guru Member

    hmm at least this explains why i can't connect to my router on serial line (i'm using sveasoft's alchemy 1.0)... do you know how i can compile my own firmware? what do i need to do this?
  8. jagboy

    jagboy Network Guru Member

    well you could do that but dd-wrt pre5 already supports that sd card reader. but the only down side is that dd-wrt is not that stable, well for me it is not stable but for most people i talked to it works for them.
  9. davidsonf

    davidsonf Network Guru Member

    You can download the source code to Alchemy 1.0. You can also download DD-WRT source code, as well as others. To use it you need two or three things. One is a Linux box. You'll also need to download the "toolchain", which is a complete development set to cross compile MIPS programs on a x86 system. DD-WRT has it available, and so does the Linksys web site.

    At that point you just need the experience required to figure out how to make it all work together. I wouldn't call it a beginner's project, but you don't need to be a professional programmer either.
  10. hedpe

    hedpe Network Guru Member

    so these serial ports...

    are they dedicated to the console? or can you hook up something like a GPS antenae made for a serial port? or like a mouse and be able to read the serial port mouse data?

    basically... can it read data!! :)
  11. davidsonf

    davidsonf Network Guru Member

    The port device is available for access by user level programs. However, it is a very basic, 3-wire RS-232 implementation, and cannot do things like hardware flow control.

    An RS-232 port has very little value other than as a console simply because the board also has 5 ethernet ports that can be configured individually. That's a lot of i/o capability and is vastly more flexible than an RS-232 port. But the big value of having an RS-232 console is so one can work on configuration of those ethernet ports without getting totally locked out by a simple mistake.
  12. hedpe

    hedpe Network Guru Member

    i'm sorry, I am new to this

    when you say it cannot handle hardware flow control? what do you mean?

    so could i plug in like a serial port mouse for example, and read data from it?
  13. davidsonf

    davidsonf Network Guru Member

    Serial ports are suprizingly complex! So don't feel bad it they confuse you.

    RS232 defines several options control lines in addition to the basic three, signal ground, transmit data, and receive data, that are needed to have a minimal serial comm link. Typically four other signal lines are also included, called DTR/DSR and RTS/CTS. These are commonly referred to as "modem control lines" in that they are usually used as control signals between a PC serial port and a modem. The RTS/CTS pair are used for "hardware flow control".

    But the RS232 serial port on the Linksys motherboard does not implement the modem control lines. Hence, no hardware flow control is possible. Typically a 3-wire RS-232 link, with only software flow control (Xon/Xoff) is perfectly adaquate for a serial console. It wasn't intended to stream large files for data transfer... :)

    Yep! (I have no idea what anyone would do with a mouse on a router, but yes, that could be done.) An example that might actually be very useful, for a remote mounted unit, would be to connect to a device that monitors the environment. Crystalfontz sells a CF633 unit with a serial interface (also one with a USB interface). A serial port on a WRT54G could be connected to the CF633, and the WRT54G can run software that deals with the CF633. That could monitor up to 32 temperature probes and control up to 4 fans or small relays. Hence this could be mounted in a box at a remote location, and control a heater, an exhaust fan, a fan blowing on the WRT54G, and still have one controller to spare. It also has at least a couple of GPIO pins available, and a watchdog function too (arranged to power cycle an ATX power supply) that could be easily configured to automatically power cycle the WRT54G if it locked up.

    I don't have any need for such a device, but I do have all of the parts necessary and have software that runs on Linux to work with the CF633. So today I ordered up the parts to add a serial port, and at some point I may end up putting all
    of that together just as a demo to watch the parts tick.

    Another odd thought just crossed my mind, because along with an RS232 adapter for the WRT54G, I also ordered one for a little GPS card that I purchased awhile back with another project in mind. I want to use the GPS to control the clock on a Linux box to give me Stratum 1 time accuracy (NTP is very inaccurate here because we get Internet via a satellite link). It would also be possible to have a WRT54G function as a time server! The problem is that it has no Real Time Clock on board, so it would have very poor holdover if the GPS lost satellite contact. But it
    could be done... (Hmmm... I wonder about an RTC too...)
  14. hedpe

    hedpe Network Guru Member

    so I am getting the feeling i soldered my serial adapter incorrectly

    i plug it into my laptop, and open up a terminal to /dev/ttyS0 with COM settings of 115200 8N1 and type in "reboot" and the device does not reboot. It also gives me nothing back.

    Shouldn't it reboot if i send it a reboot command?
  15. berndg

    berndg Network Guru Member

    i tried to apply the serial interface to a wrt54gs v1.1. can any body tell me what pin on the wrt54gs is for what purpose?
  16. u3gyxap

    u3gyxap Network Guru Member

    Try with 9600 8N1
  17. hedpe

    hedpe Network Guru Member

    nothing from 9600 8N1 either :(

    Maybe I have my pins wrong for my WAP54G

    anyone here get a working serial port on WAP54G?
  18. berndg

    berndg Network Guru Member

    Serial Port Mod

    hey i finally got my single serial port for my wrt54gs :D !! I didn't make it like the one on this page, i made it myself. So i can get into my router via serial port does anybody know which setting is used to change the transmit-power??
  19. berndg

    berndg Network Guru Member

    Hi!! I did a little research in the internet and i found out that linksys has built in a proprietary command to set up wireless options. the command is "wl". I found this on the homepage! Cool, isn't it?? :D :D
  20. Anonymous

    Anonymous Guest

    Hit "Control-C" to access serial console

    The serial won't respond until it received a "Control-C" keypress. This prevents garbage from being interpreted as commands, whether or not a console is attached.
  21. jagboy

    jagboy Network Guru Member

    maybe i am a little slow but what can you do from the serial consol. that you cant form telnet.

    i know you could use it to devrick the router.
  22. baeri3

    baeri3 Guest

    hi together, this is my first post here in this forum.. :wink:

    i have found a small project, which controlls ja small rc-car over the WRT54g[url] [/url]

    i will control a µC (AVR) over the RS232 and i have try to install this UDP server on my WRT54 but i don't work .. i have compiled the server on my debian system and than copied to the WRT.. now i get a strange error messages which look likes:
    ~ # ./updServ
    ./updServ: 1: Syntax error: "(" unexpected

    Can anybody help me? Or is there a function in the webinterface to put directly some characters to the rs232 port? If i type
    echo "my data" > /dev/tts/1 in the console, it works very fine...!
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