Q: Will this work in place of the Cisco QSFP-40G-ER4?
A: Yes. The QSFP-40G-ER4-BCC is a drop-in replacement for the Cisco QSFP-40G-ER4 transceiver. It meets the same IEEE 802.3ba 40GBASE-ER4 standard, shares the same QSFP+ form factor, and supports the same 40km reach over G.652 single-mode fibre. The module is plug-and-play compatible with Cisco equipment and delivers identical performance.

Q: Which Cisco platforms support this transceiver?
A: This transceiver works in any Cisco switch or router with QSFP+ ports that support 40GBASE-ER4 or OTU3 interfaces. The module is compatible with platforms offering 40G single-mode long-reach connectivity. Specific platform compatibility depends on the presence of QSFP+ ports and NOS support for 40GBASE-ER4 optics.

Q: What fibre type and wavelength configuration does the ER4 architecture use?
A: The module uses four separate CWDM wavelengths (1271nm, 1291nm, 1311nm, and 1331nm) carried over a duplex LC single-mode fibre pair. Each wavelength operates at approximately 10 Gbps. The internal MUX/DEMUX manages wavelength multiplexing and demultiplexing, so you only see a standard duplex LC interface with aggregate 40 Gbps throughput.

Q: Does the module support links shorter than 2 metres or longer than 30km?
A: IEEE 802.3 specifies a minimum cabling distance of 2 metres for ER4 modules to avoid receiver overload. Links longer than 30km are considered engineered links per IEEE 802.3 Table 87-6. While the module supports up to 40km under favourable conditions, links beyond 30km may require optical link budget analysis and potentially attenuation to guarantee stable operation depending on fibre characteristics.

Q: Can this transceiver operate in OTU3 mode, and what data rate does that support?
A: Yes. The transceiver supports OTU3 operation at 43.01 Gbps for optical transport network applications, in addition to 40GBASE Ethernet at 41.25 Gbps. The module complies with both IEEE 802.3ba and OTU3 specifications. BER performance is guaranteed up to 1E-12 for both modes. Your host platform determines which protocol and data rate are active.