Originally Posted by gregzoll
Um no you can not. You have no way of knowing true signal levels, etc, without the proper equipment. Just because the box shows something, does not mean that the algorithm that is used for the couple of thousand dollar test equipment the tech uses is going to show the same. What they may show is going to be completely different from what you show on the STB, DVR, or modem.
And btw, your link does nothing, since a lot of us do not use the same IP, nor have the same service as you do. Sorry, two strikes, try again.
That link, http://192.168.100.1
(generic address configured by the manufacturer, just like routers or any other piece of network gear), gets you into the cable modem (most manufacturers) where you can see exactly what is going on with it -- status, signal level, configuration, MAC addresses, and logs. It is as accurate as any $1000 or $5000 SLM. If you ever called tech support for a cable modem issue, the first thing they do is log into your cable modem to see what is going on with it.
If a tech comes out, of course he's going to throw on his SLM. Standard Operating Procedure. It's usually quicker and easier than turning on a computer, loading a browser and typing in a URL. And if there's no signal hitting the cable modem, that page probably won't come up, so he's just wasted time. Plus, with a meter, he can take a look at other frequencies on the system, such as adjacent channels, low end of the spectrum, and pilots to determine if what he's seeing is proper. I mean, in a 256QAM system, the DOCSIS carrier is -12dBc. That's 12dB lower than an adjacent analog carrier. Let's say that the bandwidth of a system is 750MHz (116 NTSC channels), with an anaolog channel (pilot) at channel 116 and that the cable modem is at channel 115. If, according to a meter, the signal level of channel 116 is +10dBmV, the signal level of channel 115 will be -2dBmV. There may be a slight variance, but very little. Load up the diagnostics page on the cable modem and he will see -2dBmV. The only limitation is that channel 115 is the only channel the cable modem can see. It doesn't care about anything else -- just channel 115.
It also tells you what the SNR (Signal to Noise Ratio) is, as well as the transmit level. Not just estimates, but actual levels. All on one page. To see the SNR with a meter, you have to change functions on the meter and hit a few more buttons, and to see what it's putting out, you have to disconnect the cable from the meter and connect the meter to the back of the cable modem and hit some more buttons on the meter to get to the right channel. If it's a DOCSIS 3.0 system, you have to go through 4 different channels to see what's going on.