If Internet connection issues with the TM7822G/CT & TM822R arise, troubleshooting may resolve the issue, or may provide insight as to what is causing the issue.  This document provides helpful information for troubleshooting Internet connection issues with the TM822G/CT & TM822R.
The following troubleshooting steps are to be followed in sequence:
- Check the physical connection
- Verify the LEDs
- Power Reset
- Verify the cable signal
NOTE: If the solutions provided in this document do not resolve the issue, please contact the cable operator for assistance.
Check the physical connection
- Verify that the TM822G/CT & TM822R power cord is connected from the power port of the TM822G/CT & TM822R to the power outlet.
- Verify that the coaxial cable is connected from the cable port of the TM822G/CT & TM822R to the cable outlet.
- Verify that the Ethernet cable is connected from the Ethernet port on the TM822G/CT & TM822R to the Ethernet port on the computer.
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Verify the LEDs
With the proper setup, the Online LED should be on, and the Link LED should either be green or yellow.  If this is not the behavior that the TM822G/CT & TM822R is displaying, please refer to this table for more information regarding LED behavior.
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Power Reset
- Shutdown the computer.
- Unplug the cable modem from the AC wall outlet and wait one minute.
- Plug the cable modem into the wall outlet.
- Wait until the Power, Receive, Send, and Online LEDs are solid.
- Restart the computer.
Verify the cable signalNOTE: If the TM822 is connected to a router, it is recommended to disconnect the router and connect the T822 directly to a computer with an Ethernet cable.
- Launch a web browser, such as Internet Explorer, Firefox, or Safari. Enter http://192.168.100.1 into the address box. The Status page will appear.
 - In the Downstream section, verify Power levels are within the acceptable range of - 15 dBmV to + 15 dBmV for each downstream channel.Â
 - In the Downstream section, identify the Modulation and Power to verify SNR levels are within the acceptable range for each downstream channel.Â
Acceptable SNR Levels (dB):Â
If QAM64, SNR should be 23.5 dB or greater.Â
If QAM256 and DPL( -6 dBmV to +15 dBmV) SNR should be 30 dB or greater.Â
If QAM256 and DPL(-15 dBmV to -6 dBmV) SNR should be 33 dB or greater.  Â
 - In the Upstream section, identify the number of Upstream Channels, Channel Type, and Symbolic Rate to verify thePower levels are within the acceptable range for each upstream channel.Â
Acceptable Upstream Power Levels (dBmV):
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Upstream Transmit Power Level |
Channel | US Channel Type | Symbol Rate | Acceptable US Power Level |
Single   | TDMA | 1280 Ksym/sec | +61 dBmV to 45 dBmV |
ATDMA | 2560 Ksym/sec | +58 dBmV to 45 dBmV |
5120 Ksym/sec | +57 dBmV to 45 dBmV |
Two | TDMA | 1280 Ksym/sec | +58 dBmV to 45 dBmV |
ATDMA | 2560 Ksym/sec | +55 dBmV to 45 dBmV |
5120 Ksym/sec | +54 dBmV to 45 dBmV |
Three or more | TDMA | 1280 Ksym/sec | +55 dBmV to 45 dBmV |
ATDMA | 2560 Ksym/sec | +52 dBmV to 45 dBmV |
5120 Ksym/sec | +51 dBmV to 45 dBmV |
- Refresh the page at least twice to identify variations in SNR, Downstream Power, and Upstream Power.  Â
NOTE: If the either of the signal levels are outside of the acceptable range, power cycle or factory reset the modem. Factory resetting the modem will eliminate any customized settings.
 - Contact the cable provider to adjust the signal level to the acceptable level range.
Acceptable Signal LevelsÂ
Recommended Max Downstream Power Level (DPL) | Recommended Min Downstream Power Level (DPL) |
+15 dBmV | -15 dBmV |
Downstream Signal to Noise Ratio (SNR) |
Modulation | Downstream Power Level | Acceptable DS SNR |
64 QAM | n/a | 23.5 dB or greater |
256 QAM Â | -6 dBmV to +15 BmV | 30 dB or greater |
-6 dBmV to -15 dBmV | 33 dB or greater |
Upstream Transmit Power Level |
Channel | US Channel Type | Symbol Rate | Recommended Max USÂ Power Level | Recommended Min US Power Level |
Single | TDMA | 1280 Ksym/sec | +61 dBmVÂ | 45 dBmV |
ATDMA | 2560 Ksym/sec | +58 dBmVÂ | 45 dBmV |
5120 Ksym/sec | +57 dBmVÂ | 45 dBmV |
Two | TDMA | 1280 Ksym/sec | +58 dBmVÂ | 45 dBmV |
ATDMA | 2560 Ksym/sec | +55 dBmVÂ | 45 dBmV |
5120 Ksym/sec | +54 dBmVÂ | 45 dBmV |
Three or more | TDMA | 1280 Ksym/sec | +55 dBmVÂ | 45 dBmV |
ATDMA | 2560 Ksym/sec | +52 dBmVÂ | 45 dBmV |
5120 Ksym/sec | +51 dBmVÂ | 45 dBmV |