Cisco C3850-NM-4-1G Catalyst 3850 4 x Gigabit Ethernet Network Module

C3850-NM-4-1G is the entry uplink module for the Catalyst 3850. Cisco describes it as four Gigabit Ethernet ports with Small Form-Factor Pluggable (SFP) receptacles, so it takes 1G optics only; SFP receptacles cannot run at 10 Gb/s. The spare is ordered as C3850-NM-4-1G=.

In Cisco's network module compatibility matrix it is listed for the WS-C3850-24T, 48T, 24P, 48P, 48F, 24U, 48U, 24XU, 12X48U, 12S and 24S models. Cisco states that this module and the C3850-NM-2-10G are not supported on the 12-port and 24-port SFP+ models (WS-C3850-12XS and 24XS), which take 10G modules only.

It suits a switch that needs four 1G SFP uplinks and no 10G. Cisco ended sale of the 3850 family on October 30, 2020, with last date of support October 31, 2025, so spares now come from the secondary market.

Fit check: read the model label on the switch and match it to the list above before ordering. If you need 10G on the same bay, the C3850-NM-2-10G keeps two SFP ports at 1G and adds two SFP+ ports; on a 48-port model the C3850-NM-4-10G gives four SFP+ ports. More 3850 parts are on the Cisco Catalyst 2960, 3850 and 9300 hub.