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New Member

WS-C3759-48TS-E: Gigabit Ethernet port didn't light up

HW Model: C3750-48TS-E

SW Ver: 12.2 (55) SE6

I confirmed that interface didn't have 'shutdown' word.

After I connected Gigabit Ethernet port via GBIC between C3750-48TS-E(G 3/0/1) and 10k(G 1/0/4), the light on C3750 didn't come up.

The interface status shown 'down'.

Are there some setting which I miss? 

Please help, thanks.

Everyone's tags (2)

Anything in the log on

Anything in the log on startup?  This might give indication.

Is the "other end" of the connection the same kind of GBIC, i.e. SMF or MMF or copper?

Is the GBIC you're trying a Cisco one?  Some "generic" ones don't work without some special commands to activate an "unsupported GBIC:.

Is the cable correct for the type of GBIC (copper, Single mode or Multimode)?  For short distances SOMETIMES you can get away with the wrong kind of cable...

New Member

Hi pwwiddicombe,

Hi pwwiddicombe,

Thanks for your reply. I think the light didn't come up because I used the 3rd-party GBIC for the connection.

I got the error message below:

12w0d: %PM-4-ERR_DISABLE: gbic-invalid error detected on Gi1/0/25, putting Gi1/0/25 in err-disable state

And I found some info about how to use 3rd-party GBIC for the GigabitEthernet connection (Cisco didn't recommand):

service unsupported-transceiver

no errdisable detect cause gbic-invalid


After do that, the GigabitEthernet light comes up with 3rd-party GBIC.

Thanks for your help.

New Member

I think it is cause by 3rd

I think it is cause by 3rd-party GBIC connect.

After I type the command, the light comes up:

   service upsupported-transceiver

   no errdisable detect cause gbic-invalid


Thanks for your help.

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