PTT278 or PTT298?

Question

Hello,

I own a barn that was converted into a residence in 2004. I have a secondary PTT line that comes from the first floor (not far from my Freebox) and goes down to the ground floor. Due to the thick walls, the Wi-Fi is not stable. Therefore, I am considering using the PTT line to install RJ45 sockets. However, I cannot tell whether the cable is PTT 278 or PTT 298 (the cable does not protrude enough from the wall to see any indication on the sheath...). Could you tell me how to differentiate between the two?
If I have PTT 298, I will wire it this way; if it's PTT 278, I will try to pull out a more recent cable.
Thank you for your responses,
Agnès

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brupala · Accepted Answer

Hello,
what colors do you have in your cable?
The 278 is often white/blue, dark blue/yellow, blue/brown...
or red/green and black/yellow.
Additionally, it is almost never in 4 pairs, but often more: for example, 28 pairs.

wifi38 · Answer

Hello,
The 278 is hardly twisted. The 298 looks like a computer cable .....

But, because there is one, these two types of cables are not designed for high speeds.

For very quick info:

Category 3: 10 Mbits, 4 wires used.
Category 5: 100 Mbits, 4 wires used.
Category 5E: 1Gbit, 8 wires used.
Category 6 and beyond: Gbit guaranteed, 10 Giga depending on the category, but 8 wires used.

So, even if you have RJ45 category 5E connections, don't expect to get a satisfactory result on the 278, but if it's 298 and the distance is short, then, although it's not intended for this, it might work.

If you seek peace of mind, replace the cable with CAT 6 with RJ45 CAT 6.

Regards.

Tange · Answer

Thank you for your response. I'm afraid I have PTT 278... ;(

What bothers me about the rewiring is that the cable doesn't move or hardly moves when I pull on it. I'm going to have sore arms again!! :P

Agnès

Tange38 · Answer

I created an account to post a photo:    It's easier! :)

Tange38 · Answer

I opened up the sheath a bit to see if the wires were twisted. Aside from the colorless (stripped) wire, it doesn’t seem like it…

Tange38 · Answer

Well, I'm going to plug in with this cable and I'll see how it performs on the speed side!

wifi38 · Answer

Hello everyone,

Nothing beats the manufacturer's description:

Contact
contact.fr@nexans.com

Residential Very High Speed Cable 298 Grade 1 - U/UTP

Description

Complies with the latest versions of the UTE C 93-531 standard
Non-shielded twisted pair construction
Ideal for applications up to 100 Mbps such as Fast Ethernet
Ideal for Triple Play (telephone, internet, and digital TV)
Recommended for the "Multimedia Housing" label
100 Ohm cable
Complies with the European RoHS directive
Complies with the European Reach regulation

Standards
National: NF C 15-100
Description

Application
The Nexans 298 Grade 1 cable allows the distribution of high-speed internet at 100 Mbps. Based on a star topology, this cable is the first level of residential infrastructure supporting telecom services such as telephone, ADSL, and digital television channels intended to circulate on telecommunication lines.
The Nexans 298 Grade 1 cable has been recommended for all new constructions since July 2003 (NF C 15-100 and UTE C 90-483).

Construction:

Conductor: Solid bare copper
Insulation: Polyethylene - Two twisted pair conductors
Identification wire
Tear wire
Outer sheath: PVC

Environment

Designed to minimize environmental impact, Nexans cables comply with the RoHS Directive 2011/65 and the Reach regulation 1907/2006/EC.
Nexans measures the environmental impact of each of its products. Upon request, the Eco Material Declaration or the Ecopassport can be provided.

There you go, not at all suitable for high-speed.

Best regards

wifi38 · Answer

Pragmatic

Yes, Brupala, you are right, it's also what I mentioned in my first response, that said, there are the standards, and as long as there is no problem, we can bypass them, but otherwise, everything will have to be called into question. Especially since in our case, there will be no wiring recipe, making it impossible to highlight connection issues.

And category 5 has never supported gigabit (in the standard, category 5 is 100M per wire, 8 wires, 800M) unlike 5E (in the standard 125M per wire, 8 wires, 1000M) even though cat 5 allows it over short distances, but how many meters? Knowing that this depends on the type of manufacturing and the manufacturer, the quality of the connection, and the RJ 45 cores.

That's also why you absolutely need all 8 wires and a minimum of cat 5E for gigabit.

And one other small detail, all standards are indeed designed for 100m, but here again, it should be clarified that actually it’s 90m MAX for the transport and 10m MAX for the cords!

We both know it is very difficult to make it understood, for example, that a certified category 7a cable but with only wires 1, 2, 3, 6 connected will at best provide a speed of 100Mbits even though this cable supports up to 1200MHz! And there we will also need to explain the difference between 1200MHz and this cable’s capacity to achieve a speed of 10 Gbits!

So yes, Tange 38 needs to attempt the wiring as I mentioned in the first post, stating that the RJ 45 cores must meet at least cat 5E if we expect gigabit, that great care must be taken with the connection, wires as short as possible, wired according to the color standard for this cable, and have U/UTP CAT5E minimum cords. And .....

Test under real flow conditions.

So just like you, I am also an advocate of Pierce who tells us:

"Consider what practical effects we believe can be produced by the object of our design. The design of all these effects is the complete design of the object."

That's what we are both trying to do on this forum.

Regards.

Tange38 · Answer

Hello,  I have finally decided to withdraw a cat 7 cable since the municipality is announcing fiber within a year or two. Thank you for your replies. Have a nice day, Agnès

PTT278 or PTT298?

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