dslreports logo

Each cable modem, regardless of brand, is uniquely identified by its Cable Modem ID, or MAC address. Short for Media Access Control, this address is a part of the hardware on the modem, and is associated with a specific user account.

It is used when asking for assistance via Personal Message with one of our techs

If posting to the public forum - please provide your Encoded Mac found on the speedtest page
CLICK PICTURE AT RIGHT TO ENLARGE--------->>
Click for full size


As there are numerous cable modems on the market, and nearly as many that are used by our customers, below are generic instructions to locate the Cable Modem ID:

    •Generally, the Cable Modem ID can be found on the bottom of the modem, usually near or on a barcoded sticker, along with the serial number of the modem.

    •Most times the Cable Modem ID will appear after these letters MAC or EA (e.g., MAC 00-12-ab-34-cd-5e) . Some Motorolas may have only SN (e.g., SN 8386848). Only use the alphanumeric numbers that appear after MAC or EA, or on some Motorolas, the numbers that appear after SN.

    •It can be easily identified by its pattern (e.g. 00-12-ab-34-cd-5e or 8386848 on some Motorolas), which stays the same from modem to modem even if the values change.

    •If your Cable Modem ID can not be located using these tips, please check the manufacturer's user guide for the modem.

    •Also can retrieve your mac address at speedtest.rcn.net . Clicking on any of the speedtests sites (NY, PA, etc.) will load the speed test page and on the table on the bottom it says "Your Modem Mac"

    Speed Test Help

    RCN"s speed test is custom built to accurately measure data throughput between the cable modem and RCN"s network.

    This is done by passively measuring traffic throughput directly at the provider"s side of the cable modem rather than the at the client side.

    Utilizing this approach allows for greater accuracy and simultaniously accounts for traffic passing from multiple hosts behind a modem (IE: home networks).

    In addition to testing your upload / download speeds, you now have the ability to monitor your cable modem throughput.

    This may be helpful to identify malware generated traffic or to simply satisfy curiosity in determining how much bandwidth a particular application uses.

    Note: in terms of cable modem service, "forward" is the downstream or download side of your cable modem service and "return" is the upstream or upload side.

    Forward Frequency:

    Forward frequency is basically the "downstream channel" the modem tunes to for receive service.
    These channels are not viewable on your TV since it"s designated for cable modem service.
    Designated frequencies may change by location and potentially even neighborhood.
    Rest assured that RCN has selected a frequency that optimizes performance in your service area.

    Forward Power:

    The forward power level reported by your modem represents how strong the signal is from RCN"s transmission facility when it reaches your modem.

    While a value of 0 is ideal, the signal should be somewhere between +/- 15 dBmv.
    If you are just outside this range, don"t worry as long as your modem"s working all is well.
    Here's some tips you may try in an attemtp to get this number closer to 0 however, these steps only work if you are at a value that is less than 0.

    Check the coax cables in your house; ensure they"re all nice and tight.

    If you have unnecessary splitters or splitters having more ports than you need, consider removing or replacing that splitter with one containing only enough ports as you need. In general each "port" on a splitter equals about 1.5 db of signal loss. In other words, if you have a 4-way splitter with two unused ports replacing that splitter with a two-way split would be the difference between having a -10dBmv and a -13dBmv forward signal. Remember, closer to 0 is better.

    Ensuring your cable modem is on the earliest split (coming from outside your home) or no split at all helps ensure your modem works at it"s best.

    Forward Modulation:

    Just as AM and FM are two methods of transmitting radio, we also have a few methods of transmitting data to your cable modem.

    The forward modulation used is determined by the environment variables in your service area. As a result not all customers see the same value.
    This signal level info is provided by the speed test merely for information purposes.

    Forward Signal to Noise:
    This number is relative to how well your modem can hear the downstream signal.
    The higher the number the better your modem can hear us. In most cases there"s not much you can do to affect this number without impacting the power level.

    Again if you remove excess splitters and take away unused ports you generally increase this value.
    Did you know that having open ports on a splitter is a bad thing? Every port that is not attached to a TV acts is a leaking point where interference and noise can get into the cable network.
    Noise is bad. If you remove unused splitters and only install splitters that exactly match the number of connections you need you are helping improve your service in more ways than you could imagine.

    Return Frequency:

    Return frequency is the frequency your cablemodem transmits at in order to communicate back to RCN"s facilities.

    Similar to the forward frequency, the return frequency is selected by RCN and optimal for your service area and is not something you control or change.

    Transmit (return) Power:

    Represents how "loud" your modem must talk for RCN"s facilies to hear you.
    The same way you raise your voice in a crowded restaurant for someone to hear you over the background noise modems do the exact same thing.

    Only in the case of cable modem"s, the background noise your neighbors R.C. car, those power lines down the street, HAM radio operators and even that "Amplifier" that you might have purchased to enhance a picture quality.

    As with the forward power, every device between your modem and RCN"s facilities represents a degree of loss that forces your modem to talk louder.
    The same information on forward power applies in that every splitter between your modem and the outside of your house means the modem must talk louder.

    Return Channel Width:

    In terms of radio frequency, this is the bandwidth of the return channel.
    In other words this determines how much of the spectrum is used to transmit data from the modem to RCN"s facilities.

    The term here bandwidth is not the same as in data transfer.

    What's with the 'Encoded Mac'?

    Instead of posting your actual cable modem mac address, use this string when posting your modem info to public forums. This allows RCN to identify your speedtest without displaying your modem mac address.




Expand got feedback?

by drake See Profile edited by lilhurricane See Profile
last modified: 2011-11-21 11:45:56