Media Converters
Lantronix S4120-1048 10GBase-T Copper to SFP+ Fiber Media Converter
The S4120-1048 is a stand-alone Layer 1 media converter that links a 10GBase-T RJ45 port to an open SFP+ slot, so 10 Gigabit copper equipment can connect over any 10G fiber type or a direct-attach cable.
Overview
About the Lantronix S4120-1048
Many servers and switches ship with 10GBase-T copper ports, while the run to the next room or building needs fiber. The S4120-1048, part of the Lantronix ION platform and often referred to simply as the ION S4120, converts between the two at the physical layer. Data passes at line speed with no store-and-forward buffering, so it fits latency-sensitive 10G links. The copper side supports 100 m on Cat6a or better UTP with auto-negotiation and auto-MDI/MDIX.
The SFP+ slot ships empty and accepts 10GBase-SR, LRM, LR, ER and ZR fiber modules, Class I and Class II SFP+ optics, WDM SFP modules and direct-attach 10G copper cable assemblies, so one converter model covers multimode, single-mode and long-haul links. DMI reports optic diagnostics. DIP switches set copper loopback, fiber loopback and transparent link pass through, and automatic link restoration recovers from faults. Per IEEE 802.3az, the converter detects UTP length and reduces power on shorter runs.
When the S4120 is linked over fiber to a C4120 card in a managed ION chassis, it can be managed in-band and receive remote firmware upgrades. It draws 10.5 W from a 12 VDC, 1.6 A universal-input adapter and operates from 0 to 50 C.
Key capabilities
- 10GBase-T to any SFP+
- Converts a 10GBase-T RJ45 port to an open SFP+ slot that takes SR, LRM, LR, ER or ZR optics, WDM modules or 10G DAC cables.
- Layer 1 line speed
- Physical-layer conversion passes 10 Gbps traffic at line speed, suiting low-latency links between servers and switches.
- 100 m on Cat6a
- The 10GBase-T port reaches 100 m on Cat6a or higher UTP and adjusts power to cable length under IEEE 802.3az.
- Remote management option
- Paired with a C4120 card in a managed ION chassis, the S4120 supports remote in-band management and remote firmware upgrades over the fiber.
- Built-in diagnostics
- DMI optic monitoring plus DIP-selectable copper and fiber loopback help isolate faults without disconnecting the link.
How to choose the right S4120-1048 part number
There is one orderable part, S4120-1048: 10GBase-T RJ45 (100 m) to an empty 10GBase-X SFP+ slot. Distance and fiber type are set entirely by the SFP+ module you install, for example an SR optic for multimode or LR, ER or ZR for single-mode, or a direct-attach cable for short in-rack links. Mount it with WMBL or WMBD brackets, or rack several units in the RMS19-SA4-02 4-slot shelf or E-MCR-05 12-slot rack.
Configure & order
Find your S4120-1048 part number
Every orderable S4120-1048 configuration, filtered by the specs that actually differ between them. Pick what you need on the left and the matching part numbers appear here.
Complete the deployment
Accessories, renewals & add-ons
Everything sold for the S4120-1048, organized by what it does — mounting & enclosures, chassis & shelves— each with why you'd add it.
Mounting & enclosures
1 item
WMBL
WMBL
4″ [102 mm] wall-mount bracket kit for stand-alone converters size 4.8″ [122 mm] and 6.5″ [165 mm]. It is listed as a compatible accessory for the E-100BTX Series.
$16.00
2 in stock
Chassis & shelves
3 items
WMBD
WMBD
5″ [127 mm] DIN Rail Mount Bracket for all Stand-Alone Converters and 1- or 2-Slot ION Chassis.
$11.00
Ships on backorder
RMS19-SA4-02
RMS19-SA4-02
19-inch, 1U rack-mount shelf for up to 4 stand-alone media converters. It includes 4 converter mounting brackets and 3 slot blanks.
$177.00
3 in stock
E-MCR-05
E-MCR-05
19” rack-mountable 12-slot media converter rack. It supports up to twelve Lantronix stand-alone media converters in a single chassis.
Compatibility taken from the Lantronix part-number tables for the S4120-1048. Don't see what you need? Request a quote — we can source the full Lantronix catalog.
Where the S4120-1048 is used
- Connecting 10GBase-T servers to fiber switch uplinks
- Extending 10G copper ports between buildings on single-mode fiber
- Bridging 10GBase-T equipment to DAC-connected switches
- Remotely managed 10G links tied to an ION chassis
S4120-1048 FAQ
What SFP+ modules work in the S4120-1048?
The open SFP+ slot supports 10GBase-SR, 10GBase-LRM, 10GBase-LR, 10GBase-ER and 10GBase-ZR modules, Class I and Class II SFP+ fiber modules, SFP modules using WDM, and direct-attached 10G copper cable assemblies. The slot ships empty.
How far can the 10GBase-T port on the S4120 reach?
The RJ45 port supports 100 m on Cat6a or higher UTP. Under IEEE 802.3az, the converter detects cable length and lowers power consumption on shorter runs.
Can the S4120-1048 be managed remotely?
Yes, when it is linked over fiber to a C4120 card installed in a managed ION chassis. It then supports remote in-band management and remote firmware upgrades. Stand-alone, it operates unmanaged with DIP switch settings.
What power supply does the S4120-1048 use?
It uses an external AC/DC adapter with universal AC input and 12 VDC, 1.6 A output. Power consumption is 10.5 W, and the converter operates from 0 to 50 C.
