The XLCNE2 single mode boards are designed to be used in applications not shorter than 7Km. The single mode XLCNE2 boards use a laser light source to support the longer distance. If these boards are used for shorter distances than 7Km, the high light intensity will damage the receivers.

The XLCNE & XLCNE2 cannot be mixed on the same fiber. A XLCNE2 can only talk to another XLCNE2. The same is true for the XLCNE.
For systems with XLCNEs, If the Total Network Length exceeds 10 Kilometers, modifications to every LCN interface in the LCN system is required. That is every LLCN board needs to be replaced by an XLLCN board and every K2LCN/K4LCN board needs to be replaced with an XK2LCN/XK4LCN board and for GUS stations the LCNP4 needs to be replaced with the XLCNP4. Not designed for lengths under 7KM.