Guide to ADSL and Cable modem Statistics

Downstream Margin & Upstream Margin (SNR)
<6db - Bad with no line synchronization or intermittent sync problems
7db-10db - Fair
11db-20db - Good with little or no synchornization problems
20db-28db - Excellant
29db or above - Outstanding

Cable modem might stop working properly if SNR drops below 23.5db.It should be 30db or higher.

Signal-to-noise ration (SNR) - ratio of signal power to the noise power corrupting the signal. The higher the ratio, the clearer the signal.

Downstream & Upstream Line Attenuation Rates (loop loss): cable length from the exchange to your wall socket. The lower the better. It is the reduction of ADSL signal strength that occurs on the copper pair over distance.The maximum reported attenuation figure with the majority of routers is 63 or 63.5db.

Line Attenuation Rates, ADSL1 and ADSL2 or 2+

Attenuation.....Approximate Line Length.......Potential Connection Speed
32db........................2.3km..............................16000kbps
35db........................2.5km..............................14500kbps
40db........................2.9km..............................11800kbps
45db........................3.2km..............................8500kbps
50db........................3.6km..............................6500kbps
55db........................4.0km..............................4500kbps
60db........................4.3km..............................3200kbps
65db........................4.7km..............................2000kbps

ADSL1 and ADSL2 or 2+ Line Attenuation Rates
20bB and below......Brilliant
20dB to 30dB...........Excellent
30dB to 40dB...........Very Good
40dB to 50dB...........Good
50dB to 60dB...........Poor and may experience connectivity issues
60dB. and above......Bad and will probably experience connectivity issues

Upstream Transmit Power - Power Level should be between -5db and +5db for best performance.
Cable: +8 to +58 dBmV. Should be less than 55dB. The lower the number, the better the connection.

Downstream Received Power
Cable: -15 dBmV to +15 dBmV
Best to be in the -8 to 8 dB range.

VOIP

Jitter - amount of time it takes for packets of data to arrive after they are being sent. Data packets might be dropped during a delay, cuasing speed quality to be distorted. Lower the better

Packet Loss - amount of data packets dropped.

Max Pause - longest pause during transmission.

Links: Quality Test

Speedtest.net
http://www.speedtest.net/
Speedtest.net is a broadband connection analysis tool with a huge selection of geographically dispersed testing servers. Ookla provides this service free to hundreds of thousands of people every day.

FreeWebMonitoring
http://www.freewebmonitoring.com/
FreeWebMonitoring
Provide web site monitoring to webmasters and site owners absolutely free. Monitor your web site's availability 24 hours a day, 7 days a week with instant email alerts and weekly web site performance statistics.

Chase IP
http://www.tamarsolutions.co.uk
Chase IP is a Packet Sniffer, Country Locator via IP Address and bandwidth meter all in one. Chase IP also shows network computers and MAC Addresses.

http://www.dslreports.com/stest

http://www.testmyspeed.com/

http://www.bandwidthplace.com/

http://us.mcafee.com/root/speedometer/default.asp

http://resources.zdnet.co.uk/speedtest/

http://www.dslreports.com/tools - VOIP Bandwidth Tester Line Quality Tests

http://performance.toast.net/

Multiple Locations -

Steps to Check

1. Listen to the phone line for noise.Connect a telephone to the phone line. Dial a number (e.g. "1"), to replace the dialtone. When the dialtone is gone, listen to the line for any noise.
   • creaks, crackle, pop, bang (due to loose connections, spolit waterproofing)
   • background voices (crosstalk lines)
   • gsm interference (place modem far away from any GSM communication)
2. Use a spare phone unit to make sure that the nosie isn't caused by a bad phone.
3. Remove unnecessary splitters.