USB to SERIAL (PL-2303) console cable to administer a Linux Box?

Discussion in 'macOS' started by 4np, Sep 1, 2010.

  1. 4np macrumors 6502a


    Feb 23, 2005
    The Netherlands

    I have a MacBook Pro (MacBookPro5,3) and a Via Epia based Gentoo Linux Box (motherboard: MB Jetway J7F4K1G5S A 1500MHz Mini-ITX ) and I would like to be able to administer it using a serial console (if -for example- ssh etc fails) as I don't have a monitor and / or keyboard.

    In order to do so, I ordered an USB to Serial DB9 (male) cable from eBay ( same as: ) which uses the PL-2303 chipset. I used the 64bit driver from github to get the cable working on Snow Leopard.


    In order to connect the cable to the COM1 port of my Linux box (which is also male), I used a 9 Pin Female Serial RS232 Gender Changer Adapter ( as seen here: ) and I have setup my Gentoo Linux box to enable the console by adding "s0:12345:respawn:/sbin/agetty -L 115200 ttyS0 vt102" to /etc/inittab and ttyS0 to /etc/ttysecurity. After reboot (or issuing 'init q') the serial console should work, however I am unable to connect to it from my MacBook Pro.


    On my MacBook Pro I do a "screen -T vt102 /dev/tty.PL2303-00001004 115200" but nothing happens, and I don't see anything in the logs of my Gentoo Linux box. I have also tried 6400 baud, and vt100 terminal emulation, but no luck at all.

    In System profile the cable is listed as:
    USB 2.0 To COM Device:
    Product ID: 0x2303
    Vendor ID: 0x067b (Prolific Technology, Inc.)
    Version: 3.00
    Speed: Up to 12 Mb/sec
    Manufacturer: Prolific Technology Inc.
    Location ID: 0x04100000
    Current Available (mA): 500
    Current Required (mA): 100

    And the kernel extension is listed as:
    Version: 1.0.0d1
    Last Modified: 6/16/10 3:58 AM
    Kind: Intel
    Architectures: i386, x86_64
    64-Bit (Intel): Yes
    Location: /System/Library/Extensions/osx-pl2303.kext
    Kext Version: 1.0.0d1
    Load Address: 0x80b59000
    Valid: Yes
    Authentic: Yes
    Dependencies: Satisfied

    So the cable itself seems properly detected and it also shows up in my system.log:
    Aug 31 19:49:29 MacBookPro pcscd4191: Non-smartcard device launched pcscd Vendor: 0X67B, Product: 0X2303

    I am not entirely sure if I should have used a RS232 female-female null-modem adapter instead of using the gender changer?


    Does anybody use a similar setup and could clarify? Any help would be appreciated! :)

    ps. I have also posted this question to the Apple Discussions...
  2. Detektiv-Pinky macrumors 6502a


    Feb 25, 2006
    Berlin, Germany
    Yes, you need a null-modem adapter for this setup to work. It crosses the transmit and receive lines, similar to a cross-connect cable for Ethernet.
  3. robvas macrumors 68020

    Mar 29, 2009
    Check the /etc/inittab file for the specs on your serial port (on your Linux machine)

    They should be listed as s0, s1, etc

    s0:2345:respawn:/sbin/agetty -L -f /etc/issueserial 9600 ttyS0 vt100
    s1:2345:respawn:/sbin/agetty -L -f /etc/issueserial 38400 ttyS1 vt100

    38400 and 9600 are the most common port speeds

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