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Vodafone Sure Signal

Sure Signal - Call Audio Quality Issues

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Moderator (Retired)

This issue has the following symptoms:


  • Poor audio quality on both outbound and inbound calls
  • Particularly affects customers using a Virgin Media cable connection


If you’re only experiencing poor audio quality one-way (for example, the call sounds fine to you, but the person you are calling reports poor quality), then this is most likely due to insufficient bandwidth on your broadband connection and is not an issue with your Sure Signal.



If the person you are calling can’t hear you, this is usually caused by low upload speeds.


If you can't hear the person you've called, this is due to low download speeds.


Check if your broadband connection meets the minimum requirements.

Please run the broadband speed checker.

If your connection fails any part of the test, this indicates an issue with your Internet Service Provider and you’ll need to contact them to discuss this further.


Your connection speed will vary throughout the day, so we recommend running it at various times to get an accurate reading.


Check for planned maintenance.
Planned maintenance can cause periods of downtime, so check the forum for any planned maintenance. If there is, this will be announced at the top of the Sure Signal forum.


Reset your Sure Signal:


Sure Signal version 1


  • Connect device to internet and power supply


  • Press and hold down the reset button (located near the internet port) until end of the process which will be indicated


  • Remove the power cable at back of the unit and wait for five seconds


  • Reconnect the power cable back to device


  • Wait for the LED sequence to flash from top to bottom and back to top


  • Wait for five seconds


  • Release the reset button


  • Within 10 minutes, all the 4 LEDs will start to flash in sequence – 1st & 3rd then 2nd & 4th then 1st & 3rd – with the sequence repeated. This sequence indicates the start of the factory reset procedure.


Sure Signal version 2


    • Connect device to internet and power supply


    • Press and hold down reset button – located near the internet port


    • Wait for all the LED (power + 2 white LED) to light up for few seconds (power LED will always remain lit)


    • Wait for five seconds


    • Release the reset button

    • Within 10 minutes, 2 white LEDs will start flashing continuously – power LED will always remain constant in addition (unless there is an issue with local connectivity)


Sure Signal version 3


    • Connect device to internet and power supply


    • Press and hold down reset button – located near the internet port


    • Wait for 20 seconds


    • Release the reset button

    • All the LEDs will temporarily switch off for about 10 seconds. The power LED will then light up and remain constant whilst white internet LED flashes continuously.


The Sure Signal will be back online in around 1 hour.


Move Your Sure Signal Away from the Router
Sometimes the Wi-Fi signal from the router can interfere with the 3G signal from the Sure Signal and this could result in poor audio quality.


In order to prevent this from happening, please ensure that your Sure Signal is moved away from the router as far as the cable will allow.


If you’re still experiencing poor audio quality, post in this thread and we can look into it further.





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Accepted Solutions
2: Seeker

Think I may have solved the issue.


I changed my superhub Wireless to Channel 1 and suddenly I am downloading over the suresignal at 7.2Mbps rather than 300k.


I will update in the next 24/48 hours if this has really solved the problem or it is just a fluke.

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2: Seeker



Broadband Speed Checker link is not working.



"Oops! Internet Explorer could not connect to




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2: Seeker

Here’s what I did to fix this. I have a Linksys router, and in the menu pages, accessed through my internet browser,  I found the QofS (Quality of Service) settings ... in my case it was under the “Applications and Gaming” tab.

After enabling the QofS , I found two sections entitled “Device Priority” and “Ethernet Port Priority”.

The first let me prioritise traffic to two nominated devices (eg. a mobile phone ) over and above any other traffic on the router. Here I needed to enter the MAC addresses of the two phones I picked.

The second let me prioritise traffic through one particular port on the back of the router, again over and above any other traffic on the router. Here, I picked the Port number into which the Ethernet cable from the Sure Signal was plugged.

 After saving the settings, I checked the quality of the calls and they were noticeably better.

Good luck! 

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3: Seeker


when making calls or receiving calls using sure signal, the call keeps breaking up, this only happens when using sure signal. i have had sure signal for a while and this has only started to happen, the signal on the phone is full & am receiving 3g. i have tried reseting sure signal & also re-registering it with no joy. is there a fault with the sure signal??

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16: Advanced member

probably not! the tech team will ask you to give them some speed tests


audio quality is normally down to poor speeds



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4: Newbie
I changed from O2 broadband due to slow broadband speed to BT infinity. I have gone from 2mb to 55mb download speed , and from 0.5mb to 9mb upload. I had no issue with call quality on O2 despite the slow speeds, yet with BT I am getting reports from people I am talking to that the audio is cutting out. I can hear them perfectly. I have tried the following: Checked broadband speed.Download and upload speed is FAST , moved sure signal as far away as possible from router, Reset sure signal, Reset BT router . Anyone tell me if there are issues with Sure Signal and BT infinity and if so, is there a fix? Thanks Chris
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Moderator (Retired)

Hi thaigreencurry,


There are no specific issues with this combination other than a specific additional port to set up. Can you check the below items for me?


Manually configure your Router to allow port-forwarding.
In most cases, routers support a system called "Universal Plug-n-Play" or UPnP, which will setup port-forwarding for you automatically. If you have a complicated network setup, or a complex router, you may be required to enter these settings in manually.

The following details list the IP addresses and Port Numbers that need to be forwarded to your Sure Signal's internal IP address. For detailed instructions on how to do this, we recommend either contacting your ISP or Router Manufacturer, or referring to the Default Guide for your particular make and model, over at

Destination IP Addresses:

Ports and Protocols:
Port 50 - TCP/IP
Port 4500 - UDP
Port 500 - UDP
Port 123 - UDP

Port 8 - TCP/IP

Port 1723 (BT Customers only) - TCP/UDP

Please note that in the above list of IP addresses, the notation "" means the complete range of IP addresses between and

Your Router will also need to be able to assign the Sure Signal with a DNS Server address via DHCP.


Check your MTU settings

Log into your admin page for your router


Find the location of the MTU field. This varies depending on the make and model of router so you’ll need to hunt around for it.


Change the value of the MTU size to 1500, which ensures that data packets aren't lost if the Sure Signal will only handle a smaller size. If this is too high for the router, set this to the highest available level and let us know.


Log out of the router, this will usually result in a reboot.


  • Perform hard rest of the VSS unit by
  • Hold in the reset button until all the light go solid
  • Pull the power lead out with the reset button still pushed in
  • Continue to hold down the reset button and reconnect the power lead
  • Wait for all of the lights to come on the release the reset button

The VSS will now try to contact the network and download its profile. This may take anything up to 6 hours.


If these do not resolve things, please post the serial number of your Sure Signal for me so we can take a closer look.



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2: Seeker

I've had nothing but problems with my Sure Signal since i got BT Inifinity. I've ready mixed messages with some people saying Sure SIgnal doesn't work with BT Infinity and others saying it does.


My Sure Signal has two white lights on it. The left one was steady switched on, and the right one switched on and steady when i made a call. The problem was that I got very poor audio quality on every incoming and outgoing call; every other word was crackled and calls were regularly dropped.


Before moving to BT Infinity everything worked fine. I've moved the box away from the home hub, but it made no difference.


I tried to reset the sure signal by holding down the reset button at the back. The sure signal seemed to reboot itself, but then the left white light flashed constantly for about 10 minutes. I tried unplugging the power and plugged it back in, same thing.


I tried to use my phone, I'm not getting 5 bars of 3g reception so it's not connecting to the sure signal. While making the call, the left white light stopped flashing. For about 5 minutes after ending the call, both of the white lights flash constantly. After that, it goes back to being the left light only to be flashing.


My sure signal serial number is 40114606847.


I've got a great upload and download speed, ping tests come back fine too.


Any help would be greatly appreciated.

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17: Community Champion

I have a Sure Signal and BT Infinity with the SS box right next to the BT Home Hub and white infinity box. I can assure you that the SS works perfectly with BT Infinity but it does need to be set up properly and the right ports opened.


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17: Community Champion


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2: Seeker

Mine just started working. I didn't open any of the ports or anything, no changes made since my last post. I'm not sure if it just took a while to reconfigure itself after the reset, but about 45 mins after the reset i got a text messaging from Voda saying my sure signal has changed location and to update the post code (the box didn't move anywhere and the post code is still saved in the sure signal settings in my online account).


Fingers crossed it remains working and stable.

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Moderator (Retired)

Hi googs_123,


Thanks for the update, it's great to hear your Sure Signal is now fully working Smiley Happy


If you do have any further questions, you know where we are.






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1: Seeker

Do you know what the minimum upload speed is for sure signal to work ok. I can hear ok, however the person I am calling is having difficulty hearing me? I use Virgin media super hub, with an upload speed of 1.9mbs and download speed of 30mbs

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Moderator (Retired)

Hi there everyone,


If you're still experiencing issues with call quality, please can you post the results of a speedtest along with your ISP and VSS serial number so I can raise this?


  • ISP
  • Download speed
  • Upload speed




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4: Newbie

I cannot use my iPhone to call my customers, as they can't hear me, and I can't hear them.  I laso have a Blackberry Storm, which works perfectly (if I force it to 3G).  My daughter also has an iPhone4, nad she has exactly the same problems.





Suresignal SN: 21196783068


I have been through all of the troubleshooting tips, several times, to no avail.



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2: Seeker


i have a sure signal box and virgin internet connection, which has high speed tests. My iphone 3GS shows full bars signal but people i call or who call me complain of a bad reception and can't hear me properly - i can hear them. I have tried resetting the box but its still the same problem.

What can i do to fix this?

Thank you, emma.

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Moderator (Retired)

Hi there Emmac77,


Thanks for your post.


I've sent you a PM which can be accessed here. If you could follow the instructions in the PM and send us your details one of the team will be with you as soon as they can.





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2: Seeker

We had the old version sure signal last year at our house, which seemed to work fine, we then moved the box to a temporary place of residence for 8 months.  We are now back at home, and since then we have had awful, or no reception via the sure signal 


Reception is so bad that we cannot hear people at all clearly, and they cannot hear us either.  I am now also intermittently getting call-failed messages when trying to ring out.

Both my husbands HTC Mozart and my iphone 4 are affected


Lights 1,2 and 4 are constant, and light 3 generally is not lit at all, but can sporadically flicker


I have checked the postcode has been changed back to our home location, have deleted and re-registered the sure signal and rebooted several times and moved the device as far away from the router as the cables allow


Is the box faulty? The serial number is 21231786078



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Moderator (Retired)

Hi carolinewatford,


Thanks for your post here.


When it comes to poor audio quality on the Sure Signal it can sometimes be down to a faulty Sure Signal box or poor broadband speeds.


I have looked at the serial number that you have provided and it is showing as not recognised, Please can you double check the serial number for me.


Also please can you let me know the results of a speed test so we can check this for you.



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2: Seeker


Serial number is 21231786076


I did 7 tests over a couple of hours

Ping varied from 12 to 42 - although I did also get one of 250

Download from 5.2 to 14.49

Upload from 1.35 to 1.94



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