Kitz Forum

Broadband Related => ADSL Issues => Topic started by: covlad1987 on March 13, 2012, 10:20:23 AM

Title: Output Power (dBm)
Post by: covlad1987 on March 13, 2012, 10:20:23 AM

hi is this normal to have no output power on the download ? the Attenuation (dB):   48.0    26.0 =3.5km

BUT  bt exchange Distance:-   Direct:         1.85 km
    (appx)*   By Road:    2.57 km

 

Downstream   Upstream
Output Power (dBm):   0.0    12.3

Title: Re: Output Power (dBm)
Post by: roseway on March 13, 2012, 10:37:35 AM

Just a small correction: 0 dBm doesn't mean zero power, it's actually a power of 1 mW. See http://wiki.kitz.co.uk/index.php?title=Decibels#Decibels_used_as_power_measurement for more explanation.

However in this case it's almost certainly misreporting by the router, because such a low power with your attenuation wouldn't be enough for a connection. Certain types of router seem to be prone to this, perhaps because of some incompatibility with the DSLAM/MSAN.

Title: Re: Output Power (dBm)
Post by: covlad1987 on March 13, 2012, 10:47:43 AM

Quote from: roseway on March 13, 2012, 10:37:35 AM

Just a small correction: 0 dBm doesn't mean zero power, it's actually a power of 1 mW. See http://wiki.kitz.co.uk/index.php?title=Decibels#Decibels_used_as_power_measurement for more explanation.

However in this case it's almost certainly misreporting by the router, because such a low power with your attenuation wouldn't be enough for a connection. Certain types of router seem to be prone to this, perhaps because of some incompatibility with the DSLAM/MSAN.

thankyou for the info 

Title: Re: Output Power (dBm)
Post by: renluop on March 13, 2012, 01:13:39 PM

The Thompson 585 I use does not show it either, but if you view the event logs (Connections) shortly after starting the router, it's there.

Title: Re: Output Power (dBm)
Post by: c6em on March 18, 2012, 04:58:43 PM

Very common on ADSL2+ connections.
The router reports the download power OK on ADSL1/ADSLmax lines.
....but when the line is switched to ADSL2+ it reports the downstream power as zero.

I will discover in a few weeks whether mine does it as well.

Title: Re: Output Power (dBm)
Post by: hacktrix2006 on May 04, 2017, 02:56:40 AM

I have noticed this as well with the Tplink Archer V2600 (broadcom chipset) and as well as the TG 582n which is another broadcom chipset.

ADSL1 i get power reading but using ADSL2 or ADSL2+ will show 0db power so i wonder if its now a incompatibility with broadcom chipsets now with some dslam's?

There is also another thing i noticed if i go into ADSL 1 mode i am on fastpath put place the modem to ADSL2/2+ and it promptly put interleave 1 on the line work that one out.

Title: Re: Output Power (dBm)
Post by: ejs on May 04, 2017, 02:09:57 PM

I think the misreported as zero issue depends on the type of exchange equipment rather than the modem. I think BTWholesale ADSL2+ equipment with vendor code IFTN tends to give the 0.

Title: Re: Output Power (dBm)
Post by: hacktrix2006 on May 07, 2017, 03:19:04 PM

Funny enough ejs i am on ADSL 2+ with the same vendor code IFTN.

So one might say there is a bug in the firmware of the IFTN equipment?

Title: Re: Output Power (dBm)
Post by: ejs on May 07, 2017, 03:36:18 PM

Perhaps, although I'm not sure there are many stats from non-Broadcom modems available to check.

In any case, I think the IFTN equipment is still better than the TSTC equipment.

Edit: I just spotted some stats from what is presumably a Technicolor 585v8 (Infineon chip), ADSL2, showing the usual 18 dBm DS output power, and showing the IFTN vendor code. So perhaps it is the combination of modem and exchange vendors.

Title: Re: Output Power (dBm)
Post by: tickmike on May 07, 2017, 10:22:36 PM

DSLAM/MSAN type:           IFTN:0x71c8 / v0x71c8
Power (dBm):           D= 0.0      U=12.7