GLC-FE-100ZX-BCC | Cisco Compatible 100MB Single-Mode 80km (100BASE-ZX)

Q: Will this work in place of the Cisco GLC-FE-100ZX?
A: Yes. The GLC-FE-100ZX-BCC is designed as a plug-and-play replacement for the Cisco GLC-FE-100ZX. It matches the 100BASE-ZX specification with the same SFP form factor, 100 Mbps data rate, 1550nm wavelength, 80km reach over single-mode fibre, and dual LC connector. The module operates in Fast Ethernet or dual-rate Fast/Gigabit Ethernet ports of Cisco switches and routers without configuration changes.

Q: Which Cisco platforms support this transceiver?
A: This transceiver operates in any Cisco switch or router with Fast Ethernet SFP ports or dual-rate Fast/Gigabit Ethernet SFP ports that accept 100BASE-X modules. This includes platforms with ports that support 100 Mbps operation alongside Gigabit Ethernet, such as certain models in the Catalyst, Nexus, and ISR families. Confirm your platform has Fast Ethernet or dual-rate SFP capability and supports 100BASE-ZX wavelength (1550nm).

Q: Why is the 1550nm wavelength used for 80km reach instead of 1310nm?
A: 1550nm wavelength experiences lower attenuation (approximately 0.2 dB/km) in single-mode fibre compared to 1310nm (approximately 0.35 dB/km), allowing extended reach applications to achieve 80km spans within practical optical power budgets. The longer wavelength also benefits from lower chromatic dispersion effects in standard G.652 single-mode fibre. This is why 100BASE-ZX and 1000BASE-ZX both use 1550nm DFB lasers for maximum distance applications.

Q: Do I need attenuators for short single-mode fibre runs with this module?
A: Yes, if the fibre span loss is less than 8 dB. The 1550nm DFB laser in this module is optimized for long reach and can overload the receiver on very short spans, causing bit errors or link instability. Cisco documentation recommends inserting a 10 dB inline optical attenuator at each end of the link when total span loss is below 8 dB to protect receiver circuitry and maintain reliable operation.

Q: Can this module operate at both 100 Mbps and 1 Gbps data rates?
A: No. The GLC-FE-100ZX-BCC operates only at 100 Mbps as a 100BASE-ZX transceiver. While it can physically insert into dual-rate Fast/Gigabit Ethernet ports (which accept both 100BASE-X and 1000BASE-X modules), the module itself is fixed at 100 Mbps and uses 100BASE-ZX encoding. The port will negotiate or configure to 100 Mbps when this module is present. For dual-rate 100M/1G operation at 1550nm, a different transceiver design would be required.