Null modem serial cable

Discussion in 'Broadband' started by Andy1973, Apr 16, 2006.

  1. Andy1973

    Andy1973 Guest

    I have bought a new computer with a 9-pin female socket enabling transfer of
    files and more importantly settings (eg modem setup) from another computer.
    My old computer is an Advent 3604. My problem is that I don't know which
    socket on the Advent might be usable for a null modem serial cable. The
    cable has to connect to a serial port, but I'm not sure which ports are
    serial. The Advent printer port, which is serial (I think), has a 15 pin
    connection, but the cables only come in 9-pin or 15-pin configurations. Any
    advice? TIA
     
    Andy1973, Apr 16, 2006
    #1
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  2. Andy1973

    Roger Mills Guest

    In an earlier contribution to this discussion,
    Computer serial ports are invariably *male* (i.e. configured as terminals
    rather than datasets) - either as a 9-pin or 25-pin D-connector.

    If you have a 15-pin connector, it's probably a game/joystick port which is
    not what you want. The printer port on most computers takes the form of a
    25-pin *female* socket - but is actally parallel rather than serial.

    A null modem cable needs to have female connectors both ends to plug into
    the computers' male sockets. The connections will be crossed over so that
    the outputs from one computer go to the inputs of the other one, and vice
    versa.
    --
    Cheers,
    Roger
    ______
    Email address maintained for newsgroup use only, and not regularly
    monitored.. Messages sent to it may not be read for several weeks.
    PLEASE REPLY TO NEWSGROUP!
     
    Roger Mills, Apr 16, 2006
    #2
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  3. Normally, serial ports come in 9 or 25-pin varieties. Most PCs built
    in the last decade have the 9-pin variety, but you can still find the
    occasional 25-pin variety. Serial ports on PCs are always female.
    Printer ports are not serial ports, as a rule. 15-pin is also pretty
    odd - printer ports are normally 25-way male.

    Don't you have the original instruction booklet for the Advent?
    Mark McIntyre
    --
     
    Mark McIntyre, Apr 16, 2006
    #3
  4. Andy1973

    Bob Eager Guest

    For the avoidance of confusion here...

    Serial - physical port is male, cable end is thus female (9 pin or 25
    pin)
    Parallel - physical port is female, cable end is thus male (25 pin)
     
    Bob Eager, Apr 16, 2006
    #4
  5. Andy1973

    Roger Mills Guest

    In an earlier contribution to this discussion,
    No they're not, they're MALE. You *do* know the difference, don't you?!
    WRONG again - they're FEMALE. Have a look at the back of your PC!

    A serial cable needs to have a female plug to connect to the male port.
    Similarly, a parallel cable needs a male plug to connect to the female port.
    --
    Cheers,
    Roger
    ______
    Email address maintained for newsgroup use only, and not regularly
    monitored.. Messages sent to it may not be read for several weeks.
    PLEASE REPLY TO NEWSGROUP!
     
    Roger Mills, Apr 16, 2006
    #5
  6. Andy1973

    Ivor Jones Guest

    While we're on the subject, anyone know of a *reliable* USB to serial
    converter..? My new laptop doesn't have any serial ports and I have
    numerous devices requiring one. The one I bought from Maplins (best part
    of fifteen bloody quid) got me the dreaded blue screen of death when I
    loaded the driver.

    Ivor
     
    Ivor Jones, Apr 16, 2006
    #6
  7. Andy1973

    Dave Stanton Guest

    You also have to be aware that some don't give the right levels or have
    all the required lines for all applications. Bit of a bodge really.

    Dave
     
    Dave Stanton, Apr 16, 2006
    #7
  8. On Sunday, in article <>
    Funny, the one I bought from Maplins works fine.

    But it surely depends on which precise model of computer and converter
    you have.

    So show off a little, tell us what your latest flash toy is.
     
    David G. Bell, Apr 16, 2006
    #8
  9. We're using the Targus PA088E
    Well, if you're unhappy with fifteen quid, then you'll be quite
    depressed with the price of this product. On the other hand, it's
    worked fine for us (talking, via a null modem cable, to the async
    serial management port on a selection of different networking boxes).

    Plugged into Linux, it worked right out of the box, and talks just
    fine from e.g ckermit software, after setting the appropriate serial
    device name. The necessary clues are right there in /var/log/messages
    as one plugs it in:
    Indeed the device appears as /dev/ttyUSB0


    OTOH, the instructions for Windoze were emphatic that one had to
    install the supplied software and reboot, before plugging the thing
    in. So that's what I did - I've no idea what would have happened
    otherwise. After that, all I can say is that it does work on Win/XP
    (as COM4).

    By the way, this inscrutable statement on the spec:

    Connector(s) (Other Side): 1 x 9 pin D-Sub (DB-9) - female

    is probably best disregarded. "Other Side" of what??? The device
    has, as one would expect, a 9-pin *male* connector, just like a
    computer's regular serial port would have.
     
    Alan J. Flavell, Apr 16, 2006
    #9
  10. Andy1973

    David Rance Guest

    I bought one from Maplin's years ago and it was useless. Then I bought a
    Belkin one and never had any problems with it.

    David
     
    David Rance, Apr 16, 2006
    #10
  11. Andy1973

    JW Guest

    According to the site below (and the onward link), that PC
    has an Intel motherboard with D-type connectors for serial
    and parallel ports. The serial port is 9-pin, the parallel
    is 25.
    Advent 3604 PC
    http://www.uktsupport.co.uk/advent/pc/3604.htm

    It would be better to use a LAN connection for the transfer.
    The new PC at least will probably have a LAN port, but
    adaptors can be bought for £5.
     
    JW, Apr 16, 2006
    #11
  12. Yes. In this case I put my head on upside down for some reason,
    probably thinking of the cable ends.
    The back of my PC has only USB, Firewire, DVI and 100baseT ports....

    :)


    Mark McIntyre
    --
     
    Mark McIntyre, Apr 17, 2006
    #12
  13. Belkin do one that works well for me - run my eMap & Palm off it
    anyway. I have grief with my Blackberry however - the drivers for it
    won't coexist with the USB/Serial drivers for the Belkin unit. VERY
    annoying.
    Mark McIntyre
    --
     
    Mark McIntyre, Apr 17, 2006
    #13
  14. The sockets you might have are: -

    9 pin small D female (hole for the pins in the plug on the cable)
    serial port with 9 pin connector

    15 pin small D female - video out.

    15 pin medium D - game port

    25 pin large D female - serial port fully wired

    25 pin large D male - parallel port for printer.

    As a useful guide get a double ended null modem cable from Maplin, then you
    really can't go wrong: -

    http://www.maplin.co.uk/module.aspx?ModuleNo=7099&doy=17m4&QV=P
     
    R. Mark Clayton, Apr 17, 2006
    #14
  15. Andy1973

    Ivor Jones Guest

    Dell Inspiron 9400.

    Don't know the model of converter, some far eastern thing judging by the
    quality of the translation of the instruction leaflet. It told me to run a
    setup program that doesn't even exist on the disc..!

    Ivor
     
    Ivor Jones, Apr 17, 2006
    #15
  16. Andy1973

    Ivor Jones Guest

    Thanks, I'll check out that, I have a couple of bits of Belkin kit and
    they've always been reliable. What's the model number..?

    Ivor
     
    Ivor Jones, Apr 17, 2006
    #16
  17. Andy1973

    Ivor Jones Guest

    [snip]
    I know, irritating, isn't it..! I can't understand why this new beast of
    mine has THREE separate video outputs (normal monitor, DVI and S-VHS) but
    NO serial or parallel ports..! Not that I miss the parallel port, as my
    printers are all networked, but the lack of a serial port is very
    annoying.

    Ivor
     
    Ivor Jones, Apr 17, 2006
    #17
  18. On Monday, in article
    <>
    This one has the pins in three rows, rather than two.
     
    David G. Bell, Apr 17, 2006
    #18
  19. Andy1973

    Roger Mills Guest

    In an earlier contribution to this discussion,
    In that case, you're not very well placed to pontificate about the gender of
    everybody else's ports!
    --
    Cheers,
    Roger
    ______
    Email address maintained for newsgroup use only, and not regularly
    monitored.. Messages sent to it may not be read for several weeks.
    PLEASE REPLY TO NEWSGROUP!
     
    Roger Mills, Apr 17, 2006
    #19
  20. According to the site below (and the onward link), that PC
    has an Intel motherboard with D-type connectors for serial
    and parallel ports. The serial port is 9-pin, the parallel
    is 25.
    Advent 3604 PC
    http://www.uktsupport.co.uk/advent/pc/3604.htm

    It would be better to use a LAN connection for the transfer.
    The new PC at least will probably have a LAN port, but
    adaptors can be bought for £5.[/QUOTE]

    OK, so not everyone is happy with installing a new card in a PC, but
    it's not hugely difficult to network two machines, peer-to-peer. It's a
    toss-up whether it's better to get a crossover cable or a cheap switch
    from Dixons. When I did it I used coaxial cable, the old way.

    I'd be a little wary about doing this through an Internet-connected
    Router, as the easy method involves using Windows file-sharing.

    I was, however, able to connect a Windows 3.11 box with a Win98 box
    using this.

    Not being connected to the Internet, I didn't bother with DNS or
    automatic allocation of IP addresses. I used a hosts file to do the
    mapping of domain names and IP addresses -- look for hosts.sam -- and it
    can be the same for both machines.

    For instance:

    localhost 127.0.0.1
    Newbox 192.168.1.2
    Oldbox 192.168.1.3

    Sorry I can't be more specific, it's been about three years since I ran
    that system. It does depend on using fixed IP addresses -- don't use the
    automatic options.

    Once you have the Windows filesharing set up, start the copy.

    This is hugely faster than a serial lead, but can still be a multi-pizza
    operation.
     
    David G. Bell, Apr 17, 2006
    #20
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