Kitz ADSL Broadband Information
adsl spacer  
Support this site
Home Broadband ISPs Tech Routers Wiki Forum
   Compare ISP   Rate your ISP
   Glossary   Glossary
Please login or register.

Login with username, password and session length
Advanced search  


Author Topic: Can a 'bad' phone cable (RJ11 to BT plug) cause VDSL2 issues?  (Read 1942 times)


  • Kitizen
  • ****
  • Posts: 1072
Can a 'bad' phone cable (RJ11 to BT plug) cause VDSL2 issues?
« on: August 24, 2017, 02:22:06 AM »

Hi all,
Well, anyone keeping up with my ASUS stability testing thread will know that I've run into a problem that is definitely not related to the ASUS.

To briefly recap, I switched over to the DrayTek Vigor 2860ac the other night and immediately got error seconds and CRC errors for no apparent reason. I then started another process of elimination. The problem however appears intermittent. So anyway, I started with turning off the homeplugs which didn't seem to make much of a difference. I then moved on to changing the RJ11 cable (internet) and the SSFP (tried another filter). No luck. I then decided to buy myself a cheap portable radio I could tune to around 600 KHz, I used the radio around the master socket and thought maybe something near the master socket could be causing some interference. So, I moved everything I could away from it. Reconnected the DrayTek and immediately got CRC errors. I then used an analogue phone and did a quiet line test, first time I didn't hear anything then the second time I heard hissing after a while (gradually getting worse over time). Finally I changed the cable from the phone to the socket and so far the problem hasn't reoccurred.

So my question is whether a phone cable, the RJ11 to BT plug one, can really cause problems for VDSL2 if it has developed a fault somehow or whether this might be something else like an intermittent fault that I'll need to contact the phone provider about (and for the current moment I'm just having a quiet patch from the fault)?


  • Global Moderator
  • Senior Kitizen
  • *
  • Posts: 23955
  • Over the Rainbow Bridge
    • The ELRepo Project
Re: Can a 'bad' phone cable (RJ11 to BT plug) cause VDSL2 issues?
« Reply #1 on: August 24, 2017, 05:14:36 PM »

In a one-word answer: "Yes".

Think in terms of a simple block diagram where the central object is a capital Y. One arm is to the outside world, another arm is to your modem/router and the third arm is to a telephone. All three arms are connected together. A fault on one can have an affect on the other two.
:cat:  100% Linux and, previously, Unix. Co-founder of the ELRepo Project.

Please consider making a donation to support the running of this site.


  • Reg Member
  • ***
  • Posts: 191
Re: Can a 'bad' phone cable (RJ11 to BT plug) cause VDSL2 issues?
« Reply #2 on: September 27, 2017, 09:36:55 PM »

Definitely, I accidently squash the cable when putting my desk back into it' home, CRC errors  went sky high, & lost of seed.
Replace it with a RJ11 to RJ11 or RJ45 made from CAT5e cable,I found under my filing cabinet, solved all problems. :-[
« Last Edit: September 27, 2017, 09:42:16 PM by KIAB »