View Full Version : Modem, House Wiring, or Gremlins

26-06-2004, 02:42 PM
This little problem is driving me nuts so please bear with me.

The neighbour asked me to look at his kidsí computer as it had just about slowed to a halt.
The long and short of it was although it had NAV it was a couple of years old, had never been updated, and the subscription had expired after 12 months. Ad-aware and Spybot recognised 1500 keys, files whatever. Index.dat was several megs so I decided a reformat and start again might be the smart way to go. This done everything worked fine at my place but the modem will not connect to Xtra from the neighbours place. It dials, squeaks and squawks, but fails to connect. Now remember it works 100% from my place and floating the mouse pointer over the two little computers on the bottom task bar shows the connection speed a very respectable 56K. (That too is at my place) My own computer only registers 44K. By the way the neighbour lives 2 doors from the local telephone exchange and I live three so there should be no problem with line loss.

Because everything works fine at my place I started to wonder about the house wiring at the neighbours. He has what I believe to be the redundant 3-wire system with 5 jack-points. Thatís jack-points not phones. The bedroom phone was unplugged for the benefit of the testing. Closer inspection doesnít reveal anything obviously wrong but I note that there is an object called a ďTest Termination UnitĒ hung across the ďAĒ & ďBĒ legs in the termination box at the entrance to the house. Could somebody please explain to me this little black box?

Ok, I then thought getting Telecom to test the line would be a good idea which I did and they claimed they could find nothing untoward. Darn, now if that wasnít bad enough a young fellow turned up with his Acer Notebook and hooks straight onto Xtra at 44K.

Can someone please suggest something as Iím fresh out of ideas? :(

26-06-2004, 02:59 PM
what OS? what modem and what drivers is it useing ?

26-06-2004, 03:28 PM

OS win98se

Modem Conexant HCF V90 Speakerphone PCI Modem

Port Com 3

Comm.drv 5872 bytes date 4/23/1999

Identifier PCI\CXT1035

Driver file details

Provider Conexant

File Ver

Date 5/13/1999

Graham L
26-06-2004, 03:29 PM
I suspect the test termination unit should be removed. I think it pretends to be a phone so line testers give a normal response. Telecom's test will have checked that the line is fine for telephones. Wet string works for telephones. :D

The three-wire system is "deprecated" these days. The third wire is fed through a capacitor in the first phone and drives the bells in other phones. It gives an imbalance which might affect the frequency and phase response, which both matter in modern modems. The other problem can be the often branched configuration.

But the modem worked before. The only thing you have changed is the software. :D

Check all the settings of the modem. For example, is it set up to work in NZ? ;-)

26-06-2004, 03:52 PM
If the same PC connects fine from BM's place, then it is hardly likely to be software.

1. Check the modem cable - are you using the same one?
2. Are you connecting through the main jackpoint (where the line enters the house) or an extension? The main jackpoint (for purposes of testing) is best.
3. Be sure all extraneous devices (phones, double-jackpoint plugs, etc) are removed and add each one back on after a successful connection.

26-06-2004, 04:21 PM
I'm probly way off track here but do you need to put any extra numbers in the dialup, eg for disabling caller waiting or anything like that?

Just a thought. ;-)

26-06-2004, 04:29 PM
I donít recall being asked where in the world I was during the modem set-up Graham. Iíll follow that up.

But it doesnít really explain why it goes like a rocket at my place but not next door does it? (Unless the world has been re-surveyed without my being advised) ?:|

Your observation that it used to work ok at the neighbours is oh so correct, going by the garbage that it had downloaded over an extended period. :D

Iím very tempted to take my side cutters to the wiring and remove the test termination and the third wire set-up. I know telecom insist you must replace the termination box to convert 3-wire to 2-wire but these are not the square cream boxes, they are flash stainless faced types I havenít seen before. The insides look normal thou. I recon just cutting the leg of the capacitor connected to line and removing the ringer wire from pin 3 should do it?????? ]:)

By the end of the weekend the neighbour may well have no computer or phones! :)

Yes antmannz I made sure it wasnít the cable between modem and connector box and yes the connection is on the main jack.

The only thing going for this fault is that it is not intermittent if that can be considered a plus? :(

26-06-2004, 04:39 PM
Really, really, really, really, really stupid question: The modem cable is plugged into line and not phone?

Personally, I'd snip the entire phone cable system off and re-connect it. If it works, great; if it doesn't, then re-join it to restore it to as new condition ;) . Of course you may need some joiners to do this properly.

26-06-2004, 04:56 PM
Yep antmannz, the modem cable is in the line socket, but I must admit in desperation I tried it in the telephone jack! :D

These modern day dry joints scare hell out of me, especially when you get lots of salt air as we do in Mount Maunganui.

26-06-2004, 06:51 PM
Have you tried a phone in the socket you are using, if so, was the line clear?

What about setting up a dial-up connection to a cellphone, or even your home number. That is the way I usually check that it is dialling out ok.

If it is dialling out ok, ie, the cellphone or your home phone rings and when you answer it you get the screeching sound, then there may be a problem in the hand-shaking between the PC and Xtra. Ensure that 'log on to network' is not checked, and that the only protocol under dial up networking is tcp/ip.

I'm in Tauranga, will be in the Mount tomorrow afternoon if ya want another set of eyes.


26-06-2004, 10:16 PM
No jester, log onto network not ticked and only tcp/ip ticked.

I just can't understand why it performs perfectly at my place and wont go at all at the neighbours. Siting on my kitchen table it goes as quick and as clean as any dial up I've ever encountered.

The phone sounds fine on the same connection but I'll try dialing home tomorrow.

I'll check with the neighbour in the morning if anyone will be home tomorrow afternoon.



Peter Coleman
26-06-2004, 11:09 PM
Don't remove the TTU as it is only there for testing purposes for Telecom,it is a capacitor and resistor,and the test from Telecom can see it if all the phones are removed,and can tell the line goes all the way to the house.If you have 3 wire jacks,then by rights you shouldn't have a TTU as these are only needed on 2 wire systems.As someone else said,check for a noisey line,it may be that.

27-06-2004, 12:04 AM
I recently discovered that a telephone cord will not work with a modem, even though they are visually indistinguishable. Could this be your problem? According to my new computers setup instructions, even 4 devices on 1 line can be trouble.
What's the bet that this turns out to be something that is really obvious in retrospect?

Jim B
27-06-2004, 01:56 AM
I can understand your frustration with this problem, it seems to defy any logical explanation.

There is obviously nothing seriously wrong with the phone line as it was being used before and a laptop connected no problem.
There is nothing wrong with the computer configuration as it works at your place.

You do not mention the error message or error number you are getting but I suspect it is 650 or 678 type errors which basically means the ISP modem is not answering or not responding. These are usually phone line related and I have heard of cases where
there have been connection problems due to being too close to the exchange strange as it sounds.
It could also be due to some noise problem in the house wiring which is only affecting that modem. Some modems are able to cope with line noise better than others which may explain why the laptop was able to connect.

Check in Control/Panel/ Network that only the following components are installed and remove any others.
Client for MS networks
Dialup Adapter

I suggest you lower the modem connect speed which should enable a connection if there is any phone line/modem issue which is causing the problem.

Double-click on My Computer, then double-click on Dial-Up Networking.
Right-click on the ISP connection icon and choose Properties.
Click the Configure button.
Change maximum speed to 38.400
Click the Connection tab.
Click the Advanced button.
In "Extra settings box," enter the string: +MS=V34
Click OK to save changes.
Restart the computer to activate the changes.

27-06-2004, 11:42 AM
Thanks guys, as always your efforts are appreciated.

Got the picture on the TTU Peter. (Havenít got a rellie Brian ex Rotorua have you?)

Yes Vince, Iíve seen people caught out with the connection cord also so I always make sure I use the same one. Whilst there are four or five jack points in the house there are actually only two phones connected at any one time so really speaking they shouldnít cause too much trouble.

Jim I think you might have nailed it. Were too damn close to the Telephone Exchange. It wouldnít happen to many people when you think about it would it? Now, I recall fixing a mates fax and just to test it I used Telecoms 0800 108 208 fax test facility. When the graph came back of the overall equivalent it said I should reduce the send level 5db, otherwise all was fine. I thought at the time yea, but Iím only three doors from the exchange and my mate is way down Papamoa so I left it and as far as I know itís worked fine ever since.

As an aside, I think I must have missed something as Iíve aged but in my time a db didnít mean diddly squat unless you new what it was relative to. In telephone terms it often referred to 800hz @ 1 milliwatt across 600 ohms but then you had DbV also. As the measurement was logarithmic 3db constituted double or half so in the case of the Fax above if the db referred to was dbm0 then there was call for adjustment if the machine was to reside at my place.

Anyway, for the want of a better idea Iíll try loading the line and see if the modem likes weaker signals.

Iíll keep you posted.

(I'll try those other suggestions of yours too Jim)

27-06-2004, 11:58 AM
you shouldn't need to string it, exspecially if it worked well before the reinstall.

when you tested at your house where you useing the same ISP?

also have you got the proper drivers installed rather than the generic ones?

have you installed the dailup networking upgrade?

Jim B
27-06-2004, 12:02 PM
How do you know it did not have a string added before the reinstall.

The modem drivers and dialup networking all must be OK otherwise it would not work from the other house.

27-06-2004, 12:31 PM
>ow do you know it did not have a string added before the reinstall.

you don't ;-) however i would have thought someone would have complained about the slow connection when they should have the best lines around. also the laptop conected without the need for stringing.

the drivers may be okish but funny things can happen once you add a bit of noise into the phone lines.

this one is a bit werid. in theory it should be working. the laptop proves the lines are ok. having the pc connect fine at other house proves pc is ok yet it dosn't want to run when on those lines. i have seen simaler things when running generic drivers. also xtra can be dodgy at times when the dailup upgrade is not installed (don't ask why as other isp's will work without it but xtra won't). for best performance the correct drivers should be installed, hopefully it MAY fix the problem.

Jim B
27-06-2004, 12:49 PM
> you don't ;-) however i would have thought someone
> would have complained about the slow connection when
> they should have the best lines around. also the
> laptop conected without the need for stringing.

Some people don't even know if they are connected or not let alone how fast the connection is.
Laptop has a different modem, not all modems react the same to line problems.

> this one is a bit werid. in theory it should be
> working

You can say that again, weird I mean.
Theory is fine but does not always work out. it is necessary to try things which normally should not be necessary in situations like this to see what actually happens.

27-06-2004, 01:05 PM
The neighbours not home at the moment so things are on hold.

However, the ISP is Xtra and no changes were made between houses tweake.

The drivers are what came with the modem.

Can you explain this dial-up upgrade a little fuller please tweake? Is it a Windows upgrade you refer to or something downloaded from Xtra.

All upgrades and patches were installed off the free Windows Update Disk and from Microsoftís update website.

(Hmmmm thinks I bet they werenít previously installed)

27-06-2004, 01:06 PM
The offer's still there BM, will most likely pop in and see mum in the Mount mid-late PM.

email splatty at orcon dot net dot nz if you want.


27-06-2004, 01:11 PM
Their not home at the moment Jester but thanks anyway.



27-06-2004, 01:20 PM
dailup networking upgrade here (http://www.microsoft.com/downloads/details.aspx?FamilyID=be625dbb-5afe-426a-bc0a-71aac2000ae8&DisplayLang=en)

check make/model of modem and see if there is any new drivers for it.

i assume motherboard drivers etc are installed ?????

otherwise all i can suggest is to put both pc's in their house and try them useing EXACTLY the same leads etc.

btw what is the pc's specs?

27-06-2004, 03:05 PM
Too close is usually line current related rather than level, but you're neighbours so how much difference can there be. Telecom's recommended fax levels were conservative purely because some Pacific island satellite links gave trouble at normal levels. The MS dialup networking update is most likely NOT on the security disk.

27-06-2004, 06:16 PM
Update team.

I cut the third wires (Blue pin 4) in the main jackpoint plus removed the test termination from the entry point and blow me down we have lift off. The computer connects and runs like a rocket and the two cordless phones work 100%.

Only problem is he has an ordinary phone in the garage and it no longer rings! Not entirely unexpected seeing Iíd cut the ringing wire at the main jackpoint, but I canít see for the love of me how to convert the phone back to 2 wire.

The phone is a RENTEL 410 Telepermit 202/91/002 Anyone any suggestions on this.

Iím still lost for a technical explanation as to what was annoying the modem initially. It would seem the third ringing wire was causing the problem even when no phones were connected to the jackpoints. I suppose I should check for a high resistance earth or something on one of the wires. Iíll do that tomorrow. Alternativly I guess the test termination could be series resonant to whatever frequency the Modem works at and was sucking most of the signal? Hmmmmmm I wonder? ?:|

It's all very well getting the damn thing going but I really would like to understand what the problem was! :D

Billy T
27-06-2004, 07:07 PM
I'm not sure that cutting the wire off is a complete conversion Bob. When I rewired my house in preparation for Jetstream I was advised by Telecom to convert to the new 2 wire outlets. In fact, they do not guarantee Jetstream performance on 3 wire installations. I did that throughout and had no problems.

Maybe one of our telecom techs might be able to explain. Alternatively, full data on the 2 wire standard is available on Telecom's website.


Billy 8-{)

27-06-2004, 07:12 PM
The modem should be a 2 wire device connecting to the 2nd and 5th contacts on the plug that goes into the phone socket. I've struck cords that have the 3rd wire also connecting to something at the modem end shorting the capacitor causing the 3 wire phones to ring. Quick fix was to lever the center 2 contacts out of the modem's BT phone plug.
The master jack and TTU are 1.8uF + 470K R, even a double term should have little effect at analogue modem frequencies

Peter Coleman
27-06-2004, 10:18 PM
The 410 won't ring without the 3rd wire from the master or with 2 wire jacks.What you have done is actually convert the jacks to a secondary jack,and with no 3rd wire,the phone won't ring.Go to Dick Smiths,or the Wharehouse and get some 2 wire jacks to replace them all.


28-06-2004, 08:12 AM
Yes replacement of the jacks would certainly seem the thing to do, however, the existing jackpoints are not the standard square box provided by Dicky Smith, but a larger light switch size with stainless steel face plates. As itís a rather nice house I donít think heíd appreciate the large hole in the wall that a standard jackpoint would leave when fitted.

It would seem that whilst one can turn these 410 phones into a musical instrument with adjustments for Volume, Tone, length of ring and so on you canít actually change them to two wire so as to get them to ring in the first place. :( Sooooooo, maybe some adjustment to the jackpoint like a 0.1uf capacitor slung between terminals 2 & 3 might do the trick?

However, it will have to wait a while as Iíve got to go to Hamilton and fix the mother-in-laws stove. I told her to keep the coal range! :D

28-06-2004, 01:20 PM
Dick Smith don't really have a huge range. Try your local Ideal Electrical store, they have all manner of eletrical / phone modules.

Graham L
28-06-2004, 03:50 PM
Sneaky fix: leave all the sockets connected as 2-wire. Swap the master box (the one with the capacitor in it) and the garage one. Don't connect the third wire. It will ring the 410 phone plugged into it.

Of course, this is very naughty if they are paying for internal wiring maintenance.:D

30-06-2004, 11:42 AM
Well back to the problem in hand after a lay day to try and regain some composure after a run of incredibly stupid problems. The mother-in-laws stove proved to be as tricky as the neighbours computer and telephone setup, boy am I being punished for past sins! How about this? I ask the mother-in-law what sort of stove she has? An Atlas dear comes the reply, so, off to Hamilton I go with a boot full of Atlas parts. Walk into the kitchen and here confronting me is the Atlas stove with Shacklock scrolled across the front of it. Iíd completely overlooked the fact that to this rising centurion a stove is an Atlas, shoe polish is Nugget, soap powder is Rinso and so on. I wonder who will service her Westinghouse, Trans-Rail possibly. :D Anyway, if that wasnít a bad enough start, investigation shows the oven fuse completely vaporised, they probably registered the event at Benmore and every power station in-between. Ha, I think this is easy, typical blown element just a matter of which one, usually the one with a hole in the side. Nope no holes, ok, weíll get scientific and out with the multi-meter. What the, all elements read correct resistance and none breaking down to earth. Out with the heavy artillery, the 500v meggar. Nope, insulation fine, replace the fuse, power on and everything is good as gold, made a cuppa, left stove going everything fine working 100%, so, left Hamilton with the immortal words of Arnold Schwarzenegger ringing in my ears. ďIíll be backĒ. :( I canít for the love of me think what the hell caused the problem, thereís not an arc mark to be found anywhere and looking at the fuse there has to be as I seen enough of them to tell the difference between one that has aged and finally blown and one that has been vaporised whilst doing its duty.

Anyway, back to the Neighbours computer and telephones.

I like your thinking Graham, thatíll be my next move as Dick Smith is now charging $28 for a 2 wire jackpoint. I was thinking of swapping the innards, as it were, but at the price I think weíll try some other tricks first. ]:)

05-07-2004, 06:31 PM
Just thought Iíd update this saga for those who helped out.

In the end I converted all the three wire aux jacks to two wire by cutting the wire (Blue in this case) on pin 3 and hanging a 1.0uf 250v capacitor between pins 2 & 3. The 3 wire main jackpoint got dispatched to the garage (good thinking Graham) and the test termination became redundant.

Believe it or not the computer connects at 56k and all the phones work.

Thing is, Iím still none the wiser as to what was bugging the modem with the three wire system.

Anyway, thanks everyone for your input and I hope none of you inherit the same problem.


PS the mother in laws stove is still going! Repent Bob repent!!!

06-07-2004, 12:38 AM
I'd put my money on the modem somehow connecting to more than 2 wires and shorting the capacitor. This would only matter if there was the 3rd wire connecting to another phone. 2 wire only phone cords avoid this.

Your solution is practical but the Telecom design 2 wire jacks have changes to the layout of the circuit board and the contact plating to reduce corrosion problems inevitable when you have a dc potential across 2 points. Sooner or later all jacks have insulation problems causing failure.

06-07-2004, 10:37 AM
Paul you make a good point. Iíve just checked out a selection of Modem ĖPhone leads I have and some are four wire and some are two wire. Now, it is perfectly possible that the leads got swapped when the neighbour brought his computer to my place and it previously worked because he had a two wire lead on a three wire system. Somehow, I replaced the lead with a four wire and the trouble started. Hmmmmmmm, certainly a possibility and we have no others so you may well have solved the mystery. In future I will stick to 2-wire leads for modems and that may save rewiring houses! :D

Graham L
06-07-2004, 02:34 PM
The extra capacitors won't do any harm as long as they only use "modern" 2-wire phones. :D But they could cause a bit of loading if they plug in too many phones which need three wires. If they move the garage one, that would be fine as long as it's the only one.

The reason for the Master jack (or internal wiring of the traditional phones which preceded jacks) and the 3 wires is that you should have only one capacitor for all the bells. The capacitor in the first phone, or the Master jack went to the extra wire to the other bells. More than one connected ringer/capacitor could load the line down too much. Real bells worked on 90V AC and used the capacitor to avoid shorting the DC used for dial-dialing and talking.

Two-wire does away with the capacitors. Electronic bells don't need the hefty current to make a hammer hit bells from the 90V AC -- they just detect it and generate electronic noises. You need either an internal capacitor in any (one !) traditional phone which you plug into the two-wire system, or a master socket for it. (But you don't connect it out to other sockets. or you'll be back to a 3-wire system).

The layout change on the 2-wire sockets just commons pins 1,2,3 on one side, and 4,5,6 on the other. This allows you to daisychain them with only one wire per contact, and even have a spare pair of contacts for the test unit. :D

You're unlikely to get problems the way you've done it B.M, but You could always move before they get some retro HB670s and plug them in. :D

06-07-2004, 02:58 PM
Those HB670ís you refer to Graham must have a landfill of there own somewhere. When you think about it there must have been millions of them and it took some grunt to make them ring. 70 volt AC at 16.66 hz as I recall. I also recall getting tangled up between a buss bar carrying the ringing and a buss bar carrying +130v plate voltage, that got my attention. :D