Recognizing counterfeit Cisco WIC-1DSU-T1-V2 cards is relatively easy. Turning them on won't tell you much of anything unless it explodes. This also leads to the first test: if it explodes, then it most likely counterfeit. Don't expect Cisco to help you with a warranty claim in this situation. But if it doesn't explode and turns on, then you have to look at the card to see the differences.

Here are some points to note. We believe none of these are definitive. However, each taken in summary with the other points can lead you to a conclusion on real or counterfeit.

STEWART: This can be found on the inside of the RJ45 jack. This was formerly the best indication of a legitimate card. We have many counterfeits saying Cisco. On counterfeit cards, we have observed STEWART, GLG and 6. Be certain there are more.

GREEN CISCO HOLOGRAM: Almost all Cisco V2's have Holograms. Very early versions did not have holograms. Not having a hologram can be offset by embedded numbers in the metal plate, silver points on the card, correct serial number, hi-low connectors, etc. So far, we have not observed any counterfeit WIC-1DSU-T1 V2 with a Hologram.

RJ45 JACK: On the Genuine card, it sticks out 1/16" to 1/32" and has a number of Metal attachments. On the left side it is higher than on the right and two attachments on top.

HI-LOW CONNECTORS: On the Genuine card, it sticks out 1/16" to 1/32" and has a number of Metal attachments. On the left side it is higher than on the right and two attachments on top.

SCREWS: Counterfeit cards we have observed have droopy and shiny screws. The lines are not fine and almost seem sand cast.

LED HOLDER: Counterfeit LED connectors tend to be bright red in color and not Genuine Cisco blue or Cisco Rose.

SILVER VERSUS COPPER POINTS: If you see copper colored points on the card, run. Very likely this is a counterfeit card. If you see silver, than the card is likely genuine.

SERIAL NUMBER STICKER: The serial number sticker is printed with a specific font with bar codes in a certain fashion. Please compare the photographs below for a full understanding.

EMBEDDED NUMBERS IN THE FRONT METAL PLATE: The genuine may be shiny on top but is clearly flat metal on the front. The counterfeit may seem dull or flat finished all around.

QUALITY OF CONSTRUCTION: On genuine cards, the paint does not run, welding on the attachment is clean, and chips are all straight. We have observed some counterfeit cards with messy paint, bad welding and misaligned chips.

BOX HOLOGRAM: A box with a Cisco Hologram is likely a genuine product. A box without a hologram is suspect.

 We hope this helps!  We found this information through a counterfeit site on the internet (we aren't allowed to post links) & it helped us with identifying fakes vs. authentic.