Cable Modems
(Redirected from Cable Modem)
- See also: Cable TV
Signal Levels
Signal levels can typically be viewed by navigating to http://192.168.100.1/.
Recommended Values
- Downstream (Rx) Power Level:
- -10 dBmV to +10 dBmV "Recommended".
- -11 dBmV to -14 dBmv / +11 dBmV to +14 dBmV "Acceptable".
- -15 dBmV & +15 dBmV "Maximum".
- Signal to Noise Ratio (SNR) Levels:
- QPSK: 12 dB minimum. 15 dB or higher recommended. (often used in upstream channels)
- 16 QAM: 18 dB minimum. 21 dB or higher recommended. (often used in upstream channels)
- 64 QAM: 24 dB minimum. 27 dB or higher recommended. (often used in downstream channels)
- 256 QAM: 30 dB minimum. 33 dB or higher recommended. (often used in downstream channels)
- There is no upper SNR limit; however, 40 dB is the highest most people see. Going above 40 db is possible though.
- Upstream (Tx) Power Level:
- +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.
If the values reported by the cable modem are outside of these ranges, there is probably an issue with the signal quality.
Source: What should my signal levels be?
Models
Terayon TJ-715X
This is the cable modem provided to me by Bright House Networks.
On this particular modem, detailed status information (signal strength, etc.) is hidden by default. You can access the RF Parameters by navigating directly to http://192.168.100.1/modemRfPage.
From this page, other diagnostic pages appear in the navigation bar. These pages require you to enter icu4at! as a password.
The direct "login" page for this modem is available at http://192.168.100.1/diagnostics_page.html.
