How to access your Arris Surfboard cable modem and check signal levels.

How to Access Your Arris Cable Modem

Checking the cable modem signal levels from your desk PC. One type of popular and well established modems are Motorola Surfboard (Arris) Modems. These modems have been a popular choice for both cable providers and users who purchase their own. Accessing your modem can give you a good indication of possible issues arising from inadequate signal strength or too much noise on the line that will affect the connection.

By accessing the screen pages inside your modem you should be able to gain some information on your Internet connection. Two important pages are the Status page and the Signal page, both showing a snapshot of information about your current Internet provider's Internet signal strength and potential possible issues that could affect your connection and ultimately your VoIP service.

Steps to access your Arris Surfboard Modem and check signal levels to troubleshoot your connection.

The Status Page of a Motorola modem.

Start by accessing your Arris surfboard cable modem by opening your web browser and using the IP address of 192.168.100.1 (This address is also used for older Surfboards.). Once open it should show you The default page the Status page. The most important information on this page is The Cable Modem Status which should show Operational. If a Failed appears above this information and the modem does not show Operational then the modem has failed to sync with the Cable Provider and is not connected. An Operational modem can also be determined by looking at the modem indicator lights with the Online light being solid.
The next page to get useful information and probably the most important one is the Signal page which will show certain power levels which can give an indication of a problem.

The Signal page of a Motorola Surfboard modem.

Information when troubleshooting cable modem signal levels.

Poor signal levels result in- Signal levels that are not in the acceptable parameters listed above can cause loss of connection, slow speeds and connection issues, including failure of one of the steps needed for registration with the provider, packet loss or the need for packet retransmission.

Premise hardware- On premise hardware including splitters, bad connectors, and poor quality cabling will effect cable signal levels and can cause problems. The cable modem should be a direct line from the first splitter using the leg with the least dB loss. This will allow the best level of signal from the cable box at the premise to reach the modem.

Signal level variation- Checking the modem's signal levels is a snapshot of those levels at that time. Weather and the change of temperatures affects cable hardware which can reflect in variations of the levels at the modem. It is recommended that for best performance some headroom is included in a modem's levels of approximately 3dB. Additionally, when checking the modem and finding variations that occur in a short period of time, where the signal level readings are varying sporadically is a cause for concern and may point to an issue that needs to be corrected.

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Cable Modem Signal Levels and what they mean

How to troubleshooting your Internet connection by checking the signal levels.

Modem Signal Levels

Signal levels are a good indication on the performance of the modem which then affects the connection. A modem that has levels out of range will struggle to keep a connection with the provider's head-end resulting in the modem going off line, packet loss, slower speeds and retransmits.

Levels suggested for DOCSIS 3.0 or later modems are as follows (but these levels can be used for DOCIS 2 as well):

Downstream Power Levels

Downstream signal (Rx) is the quantity of signal received by the modem from the transmitter of the cable provider's head-end. The signal is sent to each individual leg where it is then stepped down or distributed until a particular amount of that signal is then received by each subscriber's modem.

Recommended Levels: -7 dBmV to +7 dBmV
Acceptable levels: -8 dBmV to -10 dBmV or +8 dBmV to +10 dBmV
A Maximum Level: -11 dBmV to -15 dBmV or +11 dBmV to +15 dBmV
Unacceptable levels that would cause a modem to loose sync: -15 dBmV and lower or +15 dBmV or higher.

NOTE: A reading of (zero) 0dB is ideal.

Upstream Power Levels

Upstream (Tx) Transmit Power or as some cable techs also refer to as the return signal level is the quantity of signal transmitted by the modem for the receiver in the cable provider's head-end.

Recommended Levels: +35 dBmV to +49 dBmV for DOCSIS 3.0 modems.
Recommended Levels: +35 dBmV to +47 dBmV for DOCSIS 3.1 modems.

NOTE: A cable modem transmitting at higher upstream modulation rates can cause a degradation of the connection and result in slow speeds, packet loss and loss of the modem's connection. However, some modems can operate with a transmit (Tx) level up to +54.

*The transmit Tx level should have some head room. When constantly in the +50 to +54 range events can cause a higher level to occur which will lead to connection problems.

Signal to Noise Ratio (SNR)

Signal to Noise Ratio (SNR Downstream)- This reading should be above the 25dB to 27dB range, however some modems should be in the 30dB to 33dB range or higher.

Above 33dB would indicate a good clear signal.

What a cable tech can do to improve your cable connection.

To improve a downstream Rx signal there are several things that a cable tech can do if the issue lies outwards from the cable box on the premise.

Replace weathered connectors on the cable line from the tap to the premise.
For long cable runs from the tap, replace the cable to the premise with a larger new drop. Signal degrades over distance, so by using a larger cable (i.e. replacing a RG6 cable with a RG11 cable) can improve the signal by a couple of dB.
Correct issues with the tap connection if they exist.

To improve a problematic upstream Tx signal may require adjustments further up the provider's line at an amplifier or line extender (LE).

Note: Placing a house cable signal amplifier at the premise cable box can boost the Rx downstream levels, but will not help a Tx level and will most likely degrade the Tx level slightly.

Cable Modem Troubleshooting Tips

How to Access Your Arris Cable Modem

Steps to access your Arris Surfboard Modem and check signal levels to troubleshoot your connection.

Information when troubleshooting cable modem signal levels.

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