Cisco GLC-LH-SM vs. GLC-LH-SMD: Key Differences & Compatibility Guide
Cisco GLC-LH-SM is the older 1000BASE-LX/LH SFP optic; GLC-LH-SMD is its DOM-enabled successor that adds real-time diagnostics. Both run 1 Gbps over single-mode fiber up to 10 km. Engineers often grab the first “LH-SM” they see in the parts bin, unaware the “D” suffix unlocks DOM data—handy for spotting dying lasers before users complain. That…