D-Link DEM-331T 1000BASE-BX-D BiDi SFP Transceiver (40 km)
PRODUCT DESCRIPTION
D-Link DEM-331T 1000BASE-BX-D BiDi SFP Transceiver, 40 km (DEM-331T) - 5 Years Local Warranty
Gigabit over a Single Fibre Strand
The D-Link DEM-331T is a 1000BASE-BX-D bidirectional (BiDi) SFP transceiver. It transmits at 1550 nm and receives at 1310 nm over one strand of 9/125 µm single-mode fibre with a simplex LC connector, reaching up to 40 km — one fibre strand per link instead of two.
Pairs with the DEM-331R
Use as a pair: a 1000BASE-BX-U module (DEM-331R) at one end and a 1000BASE-BX-D module (DEM-331T) at the other, over a single strand of single-mode fibre.
Need help choosing? Email sales@sourceit.com.sg with your switch model, fibre type and link distance and we will match the right module for you.
D-Link DEM-331T Datasheet — Technical Specifications
General
| Product Name | D-Link DEM-331T 1000BASE-BX-D BiDi SFP Transceiver (40 km) |
| Part Number | DEM-331T |
| Series | DEM-300 Series Gigabit SFP Transceivers |
| Local Warranty (Singapore) | 5 years, supplied by SourceIT with a GST invoice |
Interface
| Standard | IEEE 802.3ah 1000BASE-BX-D |
| Connector | Simplex LC |
| Media | Single-mode fibre 9/125 µm (single strand) |
| Wavelength | Tx 1550 nm / Rx 1310 nm |
| Maximum Distance | 40 km |
Module
| Form Factor | SFP (mini-GBIC), Multi-Source Agreement (MSA) compliant |
| Power Supply | 3.3 V |
| Hot Pluggable | Yes |
| Other Features | TTL signal detect indicator; metal enclosure for lower EMI; full-duplex Gigabit |
| Safety | FDA, CDRH, TUV laser eye safety certified |
Compatibility & Software Support
Host Ports
Plugs into a standard Gigabit SFP slot on a switch, router or media converter. D-Link's datasheet does not publish a host compatibility list — send us your switch model and we will confirm before you order.
Diagnostics
D-Link's DEM-300 datasheet does not list Digital Diagnostic Monitoring (DDM) for this module.
Package Contents & DEM-300 Gigabit SFP Ordering Information
D-Link Gigabit SFP Transceivers (DEM-300 Series)
| Model | Standard | Wavelength | Distance | Part No. |
| DEM-310GT | 1000BASE-LX, single-mode | 1310 nm | 10 km | DEM-310GT |
| DEM-311GT | 1000BASE-SX, multi-mode | 850 nm | 550 m | DEM-311GT |
| DEM-312GT2 | 1000BASE-SX, multi-mode | 1310 nm | 2 km | DEM-312GT2 |
| DEM-314GT | 1000BASE-LHX, single-mode | 1550 nm | 50 km | DEM-314GT |
| DEM-315GT | 1000BASE-ZX, single-mode | 1550 nm | 80 km | DEM-315GT |
| DEM-330T | 1000BASE-BX-D, single-mode | Tx 1550 / Rx 1310 nm | 10 km | DEM-330T |
| DEM-330R | 1000BASE-BX-U, single-mode | Tx 1310 / Rx 1550 nm | 10 km | DEM-330R |
| DEM-331T (this listing) | 1000BASE-BX-D, single-mode | Tx 1550 / Rx 1310 nm | 40 km | DEM-331T |
| DEM-331R | 1000BASE-BX-U, single-mode | Tx 1310 / Rx 1550 nm | 40 km | DEM-331R |
| DGS-712 | 1000BASE-T, copper RJ45 | — | 100 m | DGS-712 |
Specifications per D-Link's DEM-300 Series datasheet (v1.02 WW, updated 31 Jan 2024).
Package contents are not listed in D-Link's datasheet — ask us if you need confirmation of what is in the box.
Datasheet & Downloads
| D-Link datasheet | DEM-300 Series Datasheet v1.02 WW (PDF) |
| D-Link product page | DEM-331T on dlink.com |
Need a PDF sent directly? Email sales@sourceit.com.sg quoting DEM-331T.
Frequently Asked Questions — D-Link DEM-331T
What do I need at the other end?
A DEM-331R (1000BASE-BX-U, Tx 1310 / Rx 1550 nm). Two DEM-331T modules will not link to each other.
How far can it reach?
Up to 40 km on single-mode fibre, per D-Link's datasheet.
How is it different from the DEM-330T?
Both are 1000BASE-BX-D; D-Link rates the DEM-330T for 10 km and the DEM-331T for 40 km.
Is it a stock item?
D-Link lists the DEM-331T as a project-based item — email us for lead time before planning a deployment.
What warranty do I get?
5 years local warranty in Singapore, supplied by SourceIT with a GST invoice.
