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Two TL-SG2008P switches not finding each other over 25m cable

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Two TL-SG2008P switches not finding each other over 25m cable

This thread has been locked for further replies. You can start a new thread to share your ideas or ask questions.
Two TL-SG2008P switches not finding each other over 25m cable
Two TL-SG2008P switches not finding each other over 25m cable
2024-02-10 17:45:24 - last edited 2024-02-18 01:58:52
Model: SG2008P  
Hardware Version:
Firmware Version:

Dear all, 

 

I appear to have a problem connecting two SG2008P managed switches together over a 25m CAT7 cable (very similarly to what is described in here: https://community.tp-link.com/en/home/forum/topic/165066 ). 

 

This happened after I replaced two existing SG108E, which were connected to a third SG2008P,  with those two SG2008P (in order to have them all in Omada and benefit of PoE for my two APs). Only one of the SG2008P (the one behind the 25m cable) fails to be recognised (led not even blinking, etc), the other one, which is close to the "parent" SG2008P, works just fine. Swapping the switches doesn't fix it, and all of them connected with shorted cables do work just fine. And just keeping the SG108E there works fine as well (except that I can't configure it in Omada nor power my AP with it, of course). So clearly, this appears to be related to the length of the cable, and be specific to the SG2008P model. 

 

However, the notice says it should support 100m cables, so I'm not even close to the theoretical limit.

 

Any idea on how to fix this, while addressing the original need (i.e. PoE and Omada)? 

 

Thanks in advance!

Ben

 

 

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#1
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2 Accepted Solutions
Re:Two TL-SG2008P switches not finding each other over 25m cable-Solution
2024-02-11 11:49:47 - last edited 2024-02-18 01:59:01

  @Benibis  very simple fix, get a new cable. Quite common in tp switch. Sensitive to the cable you use. If it's not good or pair is wrong, it won't connect.

 

 

Not to mention the long cable might go wrong easily.

 

I bet you ll get the same answer from the support as well.

ScReW yOu gUyS. I aM GOinG hoMe. —————————————————————— For heaven's sake, can you write and describe your issue based on plain fact, common logic and a methodologic approach? Appreciate it.
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#2
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Re:Two TL-SG2008P switches not finding each other over 25m cable-Solution
2024-02-17 09:10:07 - last edited 2024-02-18 01:58:52

Hi!

 

I thought I'd post this as a conclusion, for whoever might come after me: I did redo the connections once again (well, twice again, actually) with different connectors, and eventually, I got it to work. So as Tedd404 said, it's just super sensitive, and everything has to be perfect from A to Z. 

 

Problem solved... with a lot of sweat and swearing :D 

 

Ben

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#7
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Re:Two TL-SG2008P switches not finding each other over 25m cable-Solution
2024-02-11 11:49:47 - last edited 2024-02-18 01:59:01

  @Benibis  very simple fix, get a new cable. Quite common in tp switch. Sensitive to the cable you use. If it's not good or pair is wrong, it won't connect.

 

 

Not to mention the long cable might go wrong easily.

 

I bet you ll get the same answer from the support as well.

ScReW yOu gUyS. I aM GOinG hoMe. —————————————————————— For heaven's sake, can you write and describe your issue based on plain fact, common logic and a methodologic approach? Appreciate it.
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#2
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Re:Two TL-SG2008P switches not finding each other over 25m cable
2024-02-11 13:39:45

  @Benibis 

 

Get CAT6A, solid copper, 23 AWG. That's what I use for longer runs and POE. It works!

Kris K
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#3
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Re:Two TL-SG2008P switches not finding each other over 25m cable
2024-02-11 16:43:16

@Tedd404  @KJK Thanks for your replies. 

 

The cable I used is indeed solid copper AWG23, but Cat 7, not cat 6a, which I'd assume is an improvement. I did redo the connections, thinking as @Tedd404 suggested that there may have been a problem there. 

 

Unfortunately, the cable is now partly behind drywalls, so I don't feel like reopening the walls for this... I'm just about to be done with the rest of the house. So changing it will be a challenge. Also, it feels weird that the cable might be the issue, since it works just fine for the other devices I plugged. 

 

Now, reading your replies, I understand I'll need a miracle for this to work, which kind of sucks. Plan B would be to get back to the SG108E and buy a power adapter for the AP, but that somewhat defeats the whole purpose of having an Omada-based setup for the rest of the house. 

 

If anyone else has a genius idea that would solve this, I'll keep a eye on the topic, but I'll keep my hopes low... 

 

Thanks again gentlemen for your assistance. 

 

Best regards,

Ben

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#4
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Re:Two TL-SG2008P switches not finding each other over 25m cable
2024-02-11 17:31:25

  @Benibis 

 

Try this. Get a RJ45 coupler and a short unshielded ethernet cable. Use them to connect the CAT7 cable and the switch together. It may help.

 

I have never used CAT7 so I’m not going to comment on it, but you may like to google “CAT7 issues” to get some opinions about it.

Kris K
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#5
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Re:Two TL-SG2008P switches not finding each other over 25m cable
2024-02-14 11:43:23

Hi  @KJK 

 

No luck with the coupler (it was worth a shot, though). 

 

I'll make one last attempts with new connectors, and if that doesn't work, I'll probably just give up (until I have to reopen a wall, and then I'll cable in cat6a instead...).

 

Thanks for your help again!

Ben

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#6
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Re:Two TL-SG2008P switches not finding each other over 25m cable-Solution
2024-02-17 09:10:07 - last edited 2024-02-18 01:58:52

Hi!

 

I thought I'd post this as a conclusion, for whoever might come after me: I did redo the connections once again (well, twice again, actually) with different connectors, and eventually, I got it to work. So as Tedd404 said, it's just super sensitive, and everything has to be perfect from A to Z. 

 

Problem solved... with a lot of sweat and swearing :D 

 

Ben

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#7
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