You could faced with your Cisco Devices when you tried to use with non-cisco product third party SFP Module.
But I believe you will think about that SFP Module itself is not functioning properly or your Device Port is not functional at first time experience.
Well...it is not. Your Cisco Device will prompt you with below Log Message in the console.
%PHY-4-UNSUPPORTED_TRANSCEIVER: Unsupported transceiver found in Gi1/0/52
%GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR: GBIC in port 65538 has bad crc
This log message says that the port attached with third party SFP Module just disabled.
So, we need to workaround to work that. Just need to type two commane line as below,
switch(config)#no errdisable detect cause gbic-invalid
You should see Warning Message after you key-in "service unsupported-transceiver " that prompt Cisco Warranty will not cover if you use Third Party SFP Module.
no errdisable detect cause gbic-invalid means you are telling to Devices that do not disable the Port for the use of Third Party SFP Module.
One more thing, you will not able to find the document in Help of Cisco for "service unsupported-transceiver".
Your IOS must be at 12.2(25)SE and later to use that command.
Be happy working with Third Party SFP Modules.
May you all be happy.
(Be knowledgeable, pass it on then)