ethernet ?

Discussion in 'Computing and Networks' started by Mathematics!, Apr 7, 2011.

  1. Mathematics!

    Thread Starter Senior Member

    Jul 21, 2008
    I am wondering almost all LAN networks are using ethernet.

    But do all personal computer NIC use the same line codes / modulation scheme.
    Since I have 2 routers/switches and they where both purchased about 8 years a part. If I use either route/switch with my PC they work fine. So I am assuming their must be a universal line code/ modulation scheme for all NIC cards.

    If not, I don't understand how the NIC would be able to interpret different modulation/line codes ...etc ?

    Is the firmware for the ethernet nic cards and routers/switches program/wired for multiply different line codes/modulation schemes? ( I cann't see how this could be done easily)

    This question is really bugging me.

    question 2
    This question is really a continuation of of the above.
    If I plug my computer directly into the modem. The modem must understand how to send/recieve data from my nic card so on the lan side it must use some universal standard line code/modulation scheme which would answer the above question. Obviously the wan hardware side of the modem is just using the ISP providers modulation/demodulation scheme which is QAM. They could only change this provided they change your modem and their equipment to interpret your modem (CMTS) to use the same modulation scheme .
    On the lan side they must know that all ethernet device use some universal line code else their modems couldn't be used with all NIC / ethernet devices.
    Last edited: Apr 7, 2011
  2. AlexR

    Well-Known Member

    Jan 16, 2008
    Ethernet is a standard or rather a suite of standards (IEE803.x) and all ethernet devices must follow the standard to be called an ethernet device. This means that you can buy an ethernet NIC form any manufacturer and be certain that it will work with other ethernet components regardless of who made them.
    See answer above
    Even on the WAN side the modem will be following an international standard. This will depend on whether the modem is a cable modem, an ADSL modem or whatever.
    All commercial communications follow international standards and no-one other than back-yard amateurs ever write there own communications protocols. That way whenever you need a modem or a NIC you can go down to your friendly modem store and buy one knowing that it will work with your existing equipment.