Noisy VoIP line on Plusnet Hub 2 using standard phones via adapter

[#1]

I have bought a Grandstream HT-802 VoIP Adapter and it is connected to my Plusnet (BT) Hub 2 with full fibre 300 Mbps. I have tried 4 of my stock of standard telephones to find one with the best quality and none of them were very good. I have now bought a standard BT digital hands-free phone and this is much better but all the phones tried, including the new one, have a slight hum and a crackle on the line.  I have tried 2 makes of line filter and they make no difference.  I have tried repositioning the phone away from other electrical equipment and again there is no improvement.  Are there any adjustments to the router settings to give a better quality on a VoIP connection that would solve the problem? Any suggestions would be appreciated.

[#2]

@audiophile 

There's nothing on the router that would cause hum and crackle on a voip call. Its more likely to be the connection between the phone and the HT802 or the HT802 itself.

I have tried 2 makes of line filter and they make no difference. 

I'm confused slightly by that comment ? the phone should be connected directly to the HT802, there's no filter needed.

Where is your filter connected ?

[#3]

I would be suspecting the Grandstream HT-802 or your connection to it as the source of the "slight hum and a crackle on the line".

Once it's turned into VoIP it's unlikely to get that kind of interference.

Test with (say) your new BT phone plugged straight into the Grandstream HT-802.

There isn't much you can do to a Plusnet Hub 2 to impact the performance of a Grandstream HT-802, certainly as far as call audio quality is concerned..

[#4]

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@audiophile wrote:

l the phones tried, including the new one, have a slight hum and a crackle on the line.  I have tried 2 makes of line filter and they make no difference.

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How are you converting the RJ11 phone output from the Gransdstream to the compatible BT socket? Are you bodging it by repurposing an old DSL filter? Is this the line filter to which you refer?

If so, bespoke adapters can be bought for about a fiver. Whether it will fix your problem, but worth a try?

[#5]

Hi. Thanks for your response. The PlusnetHub 2 router I have is presumably very similar to the BT Smart Hub but it doesn't have a telephone socket. Unfortunately when I changed from BT to Plusnet I returned their BT hub which did have one.  The Gransdstream was supplied with an adapter to plug it into one of the ethernet sockets. I read on the internet that a ADSL filter might help so I tried inserting between the phone cable and the Grandstream box. It didn't. Can you give me more details about the filter you suggest please?  Many thanks.

[#6]

@audiophile 

The PlusnetHub 2 router I have is presumably very similar to the BT Smart Hub but it doesn't have a telephone socket. Unfortunately when I changed from BT to Plusnet I returned their BT hub which did have one. 

It wouldnt have made any difference, the BT Hub telephone socket will ONLY work with BT Digital voice.

The Gransdstream was supplied with an adapter to plug it into one of the ethernet sockets.

There should just be a standard ethernet cable connecting the HT802 NET (blue) port to one of the LAN ports (1-3) on the Hub 2

I read on the internet that a ADSL filter might help so I tried inserting between the phone cable and the Grandstream box.

The HT802 phone port is an RJ11. If your phone has a BT style plug, then there should have been an adaptor supplied with the HT802 with a BT style socket and an RJ11 plug.  Something like this

[#7]

@audiophile as several people above have advised "There's nothing on the router that would cause hum and crackle on a voip call".

Your problem will be caused by one of the other components - the phone you use, the Grandstream OR its power supply.

As for a "filter" between the phone and Grandstream that's irrelevant, ADSL filters are designed to separate phone and ADSL broadband signals when they share a copper line, that is not the situation here.

As noted above you may need an adapter to allow phones with a BT plug to connect to the Grandstreams RJ11 socket, but you presumably have one as you are using the phones. 

Note that most designs of ADSL filter have a captive lead that plugs into the BT socket (with a BT and RJ11 socket on the other side). However "some" designs have a short removeable lead that has an RJ11 connector at the filter. Remove that lead and you can then use an RJ11-RJ11 lead (e.g. a spare ADSL lead from an old router) to make it into an adapter.

Given what you've said so far I'd be sending the whole thing back, it's probably the Grandstream or its power supply at fault.

[#8]

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@HPsauce wrote:

... I'd be sending the whole thing back, it's probably the Grandstream or its power supply at fault.

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... and buy an actual VoIP phone that doesn't need an adaptor.

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@audiophile wrote:

... I have now bought a standard BT digital hands-free phone

... and send that back too, as you can claim that you could hear hum (which it should have filtered out)

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[#9]

Yes this is the type of adapter that was supplied by Voipfone, the YoIP service I as using.

[#10]

@audiophile the suggestions made by @outcast may seem a bit OTT but an all-digital solution would be a pretty reliable way of giving clarity on your calls, though perhaps going some considerable way beyond your initial question.

After a lot of messing about and reusing old kit I decided (as noted in other threads) to get compatible all-digital VOIP-specific equipment as I migrated from POTS to VOIP. My final configuration is a Gigaset N510 base station and a number of Gigaset cordless handsets, mostly R650H. I acquired this all via eBay so it didn't cost too much. All used equipment but in good condition apart from some handset batteries needing replacing.

My base station, roughly half the size of the router, hangs on the wall immediately above it. It has its own power supply but I have tried powering it from the routers USB port. That worked but I'm not sure it would be powerful enough for long calls with the handset some distance away so I didn't make that permanent.

There are, as I'm sure you're aware, many different suppliers of suitable kit, Gigaset is just one of quite a number of well-known ones.

[#11]

I have kept my analog phone simply because it has the excellent BT Call Guardian built in. As far as I am aware there are no  VoIP compatible phones / base stations that include this level of call blocking.

I get no hum or crackling.

[#12 · Accepted solution]

UPDATE

The crackle has gone!

Although I had previously  moved the VoIP adapter away from the router and other electrical equipment to see if that was the problem, I hadn’t moved it far enough. I thought I would try a long internet lead today and move it to the other side of the room and voilà it worked! Sorry to have bothered you all. I apprciate your support. What an excellent forum this is.

[#13]

@audiophile Thanks for letting us know, but that still suggests some faulty equipment somewhere as it shouldn't do that.

Either the Grandstream is over-sensitive to interference or there's something in the area where it was before that is generating excessive electrical noise.

You may not have the time or inclination, but if it was me I'd take it as a challenge and work out the culprit by switching off or moving things one at a time. At least once you know you can decide what to do as you may not want the Grandstream where it is now.

And @Baldrick1 said "I have kept my analog phone simply because it has the excellent BT Call Guardian built in.". That is interesting as I've seen many comments suggesting you can't do that. As stated the lack of spam call filtering on VOIP is a significant issue.

[#14]

You might have eliminated the hum and crackle,  but you have highlighted that something electrical is emitting electrical noise (which shouldn't happen with modern electronics) so you potentially have perhaps a failing power supply or other item with an overheating problem - which might be a fire risk.

Now that you have your Grandstream on a long lead, can you now move it around your room (while listening for hum and crackle) to identify the source of noise ?

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