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5. Signal Levels and other tests·What should my cable modem signal levels be?
·Running DocsDiag
·Alternate means of obtaining modem vital statistics
| | | Downstream (Rx) Receive Power Level:
This is the amount of signal received by the modem from the transmitter in the cable company head-end.
For all modems:
-10 dBmV to +10 dBmV "Recommended".
-11 dBmV to -14 dBmv / +11 dBmV to +14 dBmV "Acceptable".
-15 dBmV & +15 dBmV "Maximum".
Upstream (Tx) Transmit Power (a.k.a. Return Signal) level:
This is the amount of signal transmitted by the modem to reach the receiver in the cable company head-end.
+8 dBmV to +58 dBmV maximum for QPSK. (DOCSIS 1.0, 1.1)
+8 dBmV to +55 dBmV maximum for 8 QAM and 16 QAM. (DOCSIS 1.0, 1.1)
+8 dBmV to +54 dBmV maximum for 32 QAM and 64 QAM. (A-TDMA DOCSIS 2.0)
+8 dBmV to +53 dBmV maximum for S-CDMA DOCSIS 2.0 (All Modulations)
*Recommended upstream signal levels are +35 dBmV to +52 dBmV.
1. Signal levels not within specs can cause slow speeds, connection problems, and connection loss due to packet errors, packet loss, and/or constant packet retransmission.
2. It's recommended to have the modem's signal levels at least 3dB away from the maximum/minimum levels listed above due to normal temperature related signal variation. If the modem's signal levels are at the maximum or minimum limits, they may be out of spec. if the temperature changes significantly. Signal levels that vary more then 3 dB in a 24-hour period usually indicate a problem that should be looked into.
3. Excess splits, bad connectors, and/or poor quality cabling will certainly effect cable signal levels and will cause problems.
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by drake  edited by lilhurricane
last modified: 2009-10-25 14:01:06 | | | You can use a program called DocsDiag to extract information from the modem. You'll need to temporarily change your computer's or router's IP address when running the program, but you won't have to change any wiring. If your computer is connected directly to the modem, you can use the following instructions if you're running Windows 98/98SE; if you're running another OS, you should determine how to change your PC's IP address before proceeding. (If you have a router, it doesn't matter what OS you're using.)
1. Visit the DocsDiag home page and download the docsdiag.zip file. Unzip the downloaded file to extract docsdiag.jar.
2. Change your IP address to 192.168.100.2 and subnet mask to 255.255.255.0. You can use one of the following methods if it applies to your system (note your current settings before you change them):
If your PC is connected directly to the modem and you use Windows 98/98SE, click Start, Settings, Control Panel. Double-click Network. On the Configuration tab, click TCP/IP for your Ethernet adapter, then click Properties. On the IP Address tab, select Specify an IP Address, enter an IP address of 192.168.100.2 and a subnet mask of 255.255.255.0. Click OK and OK. Reboot if prompted.
If you have a Linksys router, go to the router's setup page and select specify an IP address, enter an IP address of 192.168.100.2, a subnet mask of 255.255.255.0, and a gateway of 0.0.0.0.
If you have a Netgear router, go to menu 4, change IP Address Assignment to Static, IP Address to 192.168.100.2, IP Subnet Mask to 255.255.255.0, and Gateway IP Address to 0.0.0.0.
3. In the MS-DOS window, enter the following command:
For machines with Microsoft's Java Virtual Machine
jview /cp docsdiag.jar docsdiag
For machines with Sun's Java Runtime Environment
java -cp docsdiag.jar docsdiag
This should produce output with your signal levels and firmware version.
4. Put your IP address back to dynamically assigned by restoring the original settings you changed in step 3:
For a direct connection to the modem, go back to the TCP/IP Properties dialog box and select Obtain an IP address automatically. Reboot if prompted.
For a Linksys router, go back to the router's setup page and select Obtain an IP address automatically.
For a Netgear router, go back to menu 4 and change IP Address Assignment to Dynamic.
In addition, the following works for Toshiba modems:
To access the built in diagnostics, set your ip statically to 192.168.100.2, set your subnet mask to 255.255.255.0 and set your gateway to 192.168.100.1. Enter 192.168.100.1 into your browser you'll see the diagnostics page.
FAQ credit to Bobcat
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by lilhurricane | | | If Docsdiag does not work for you here's another way to find this information.
Go to »speedtest.rcn.net , pick any server.
At the bottom of the screen you'll see your modem's vital statistics including the highly sought after MAC.
Click for larger view
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by jsolo1 edited by lilhurricane
last modified: 2006-11-07 21:44:25 |
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