Where to Buy Eircom Standard Broadband Telephone Cable

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newstemp

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A few weeks ago our Eircom 8MHz BB connection stopped working properly.

The rightmost "DSL" LED would go red, then the neighbouring green "Internet" LED would start flashing for about a minute, get faster, then the DSL LED would switch off for a few seconds, then back on steady green. The internet connection would now work for about 30 seconds, then the sequence would repeat.

Eircom could see the fault logged at their end, and after testing to make sure that the DSL filters were not at fault, then sent a serviceman to test the line.

He found no fault outside the house, so he tested the signal quality inside. The noise safety margin showed 14(good)-22(very good) at the entry junction box, however 6.5(marginal) at the end of the 15-20m extension cable used to connect the modem. Two other similar length extension cables showed similar results.

My first question is, why did this type of cable work for years with a BB modem in this house, and in other houses that I have lived in, then suddenly stop working a few weeks ago ? I checked today and this flat type of telephone extension cable is still being sold in 20m lengths in hardware stores with BB listed as an application on the package.

The serviceman suggested that Eircom may have upgraded the BB speed at the exchange without informing us, however Eircom report that we have had a 8MHz connection for years and no exchange modification was logged.

The second and third questions are, where can I buy the same type of BB capable telephone cable that Eircom uses to connect to the house ?, and what is the specification for this cable (most importantly it's line pair characteristic impedance) ?.

I would like to run some of this type of cable from the junction box to the modem. The serviceman did recommend using the entry junction box screw terminals rather than the RJ11 plug in connection.

Thank you.
 
Had problems before with eircom and there engineers testing the line and equipment. Always came back to one thing the modem needing to be replaced. I am suprised he didnt replace your modem to check to see if this resolved the issue.

You could test this by connecting up the modem at the closest working telephone point in the house remove all the extention cables you were using. If it works then its a cable issue and if the cable is moved a lot and not set in place the cable could have been damaged.
 
The modem was tested at the closest point and it does work there. However it is very unlikely that it is a cable change since two other cables show the same effect, and the cable is mounted out of the way on the ceiling.
 
As Leo said above any Electrical Wholesalers will do.

Just get some 4 pair Cat.5 cable.
 
Some electrical cable suppliers also supply the fittings and will connect them to the cabling for you. Enquire if they can make up a completed cable
 
newstemp said:
The modem was tested at the closest point and it does work there. However it is very unlikely that it is a cable change since two other cables show the same effect, and the cable is mounted out of the way on the ceiling.
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Just a side note if the cable running past any high powered equipment or fluorescence lighing these can effect the cable.
 
I looked at the telephone cables available and found two categories, the BT CWxxxx coded products and the Internet Cat5e/Cat6 cables. The latter have a nominal electrical impedance of 100 ohms while the former do not have an electrical impedance specified in product literature, though it may well be specified in the BT specs themselves. I have not found any of the specs, only the product literature. Cat5e/Cat6 does appear to be used commonly for telephone/DSL applications so the characteristic impedance may well match, however I would like to verify this.

The BT spec. cables include the internal use flat type, CW1311, that was in place, the internal multi-pair twisted pair type such as CW1308, the external multi-twisted pair type such as CW1128, and the external CW1411 "drop wire" with a high tensile steel strainer wire.

The two pair CW1308 has the advantage over Cat5e/Cat6 of a narrower diameter and will probably suffice in our case considering that it is said to be used for DSL applications by BT and should match the characteristic impedance of the outside telephone line. I will certainly no longer use the CW1311 flat type for long range DSL.

There is more than one wire thickness option for the CW1308 and we need the 0.5mm OD wires for any RJ11 IDC plugs, though I will make direct screw in connections where possible. There are many more sellers of Cat5e/Cat6 on Ebay than those of CW1308, and the prices tend to be cheaper.

The local trade suppliers do not supply CW1308 by the meter, only in 100m lengths, though they do supply the outside cable by the meter, so I have made a purchase on Ebay.

Interestingly our outside cable was made by Wessel Cable Ltd., a company bought from Swedish ABB by UK B3 Cable Solutions in 2006, however Wessel Cable Ltd. now no longer exists. The 1988 cable carries a marking something like CPI 2P05 (the P's may be F's), but no BT spec. The local trade store outside cable is made by General Cable and has a BT spec. (CW1128 if I remember correctly). It is available locally in 5 and 10 pair form, and much greater pair numbers elsewhere.

The path of the internal DSL cable takes it to within about 18" of an 11W flourescent light bulb (this did not change recently, though a bulb drive component might have failed). If the CW1308 does not work near the bulb I will test it away from the bulb and reroute or shield if necessary.

According to a Mayo News Oct/2012 report there is a recent government plan to reach BB data rates of 30 - 100 MHz range in every home/business in Ireland by 2015 and if so internal cable quality issues can only increase.

I do not know if this plan means that every location is to have either fibre to the home/business (highest speeds), or fibre to the ("kerbside") cabinet (then copper to the home/business, lower speeds) available, nor what is Eircom's current position on the issue. A pilot operation appears to have been formally switched on about a year ago.
 
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Make sure when buying the cable that the wires inside the cable are blue and orange wires. If you buy a cable with red black yellow and green the broadband will not work very well.
 
joer said:
Make sure when buying the cable that the wires inside the cable are blue and orange wires. If you buy a cable with red black yellow and green the broadband will not work very well.
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The sheath colour makes no difference whatsoever!!
 
No Leo the the cables inside the covering does make a differance though. Thats why I say the blue and orange wires inside the sheeting are twisted and not straight. This has a big bearing on whether the broadband will work or not.
 
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