I mentioned that in my Dangerous Things RFID card post that my office suite ingress reader scans for both LF and HF RFID tags. The building ingress, however, is purely LF. So it seems that if the company decides to switch to HF internally, then employees would either need to carry two fobs, or a dual LF/HF fob, which is less likely.
I say that a dual fob is less likely because in practice, it doesn’t seem like most small businesses program their own cards/fobs — instead, they buy pre-programmed random fobs/cards in bulk and add them to their systems. Fob/card programming only seems necessary in larger enterprise systems where building/department ID codes come into play. Also, interaction between building management and company management, and coordination of security within physical space, seems infrequent. But I mention the possibility because dual fobs do exist.
In researching the dual fobs, I also learned of the existence of UHF RFID tags, with have a longer range (1-10m), which I hadn’t looked into before.
Here are videos of the Dangerous Things RFID card testing the building ingress reader, which looks to be a typical HID reader like a ProxPro 5355, and the suite ingress reader, which reads both LF and HF.
I would also like to note that I’m not responsible for physical security in my office, company or building. I’m just curious about all things security, including the physical security domain of infosec.