GLC-BX40-DA-I-BCC | Cisco Compatible 1GB Single-Mode 40km (1000BASE-BX40-DA) Industrial

Q: Will this work in place of the Cisco GLC-BX40-DA-I?
A: Yes. This transceiver matches the GLC-BX40-DA-I specification: SFP form factor, 1.25Gbps data rate, 1000BASE-BX40-DA standard, 1490nm Tx / 1310nm Rx wavelengths, 40km reach over single-mode fibre, and industrial temperature rating. It is plug-and-play compatible in any Cisco platform with SFP ports that supports the original part.

Q: Which Cisco platforms support this transceiver?
A: This module works in Cisco switches and routers with SFP slots that support 1000BASE-BX BiDi optics, including industrial and enterprise platforms. Compatibility is determined by the presence of an SFP port rated for 1G operation and support for BiDi modules per the platform datasheet. Confirmed platform families include Catalyst, Nexus, ASR, ISR, and IE (Industrial Ethernet) series with appropriate SFP interfaces.

Q: Why must I use this with a GLC-BX40-U-I or complementary upstream transceiver?
A: BiDi transceivers use wavelength-division multiplexing over a single fibre. This downstream unit transmits at 1490nm and receives at 1310nm. The far-end upstream unit must transmit at 1310nm and receive at 1490nm to complete the bidirectional path. Connecting two downstream units (both 1490nm Tx) will not establish a link because neither can receive the other's wavelength.

Q: What is the actual link budget and can I use this at distances shorter than 40km?
A: The module provides approximately 22dB optical budget between minimum Tx power and receiver sensitivity. At shorter distances (under 5km), high received power may saturate the receiver; check the datasheet minimum received power specification. For distances under 3km, an inline attenuator (5-10dB) may be required to stay within the receiver's dynamic range and avoid bit errors.

Q: Does the industrial temperature rating affect optical performance or link stability?
A: No. Industrial-grade components and thermal management maintain stable optical output power, wavelength accuracy, and receiver sensitivity across the full -40°C to +85°C range. The module's laser wavelength, Tx power, and Rx sensitivity are specified and tested at temperature extremes to ensure the link budget remains sufficient for 40km reach regardless of ambient conditions.