Cisco GLC-LH-SM compatible ASF13-24-20-D 1000Base-LX SFP transceiver, 1310nm, 20KM I use it on Cisco 2960. It works fine for the first time, but it can’t work after I plug it out and test another transceiver. It said: HAS BAD CRC.

Solution: Please restart the port on switch or restart the switch. It may be that the port is down, because the tested transceiver is not Cisco compatible.

Tips:If you test some products to make the port or switch down, please restart it before you apply any other products on it.