The TL-SM321B-2 from TP-LINK is designed according to the Small Form Pluggable Multi-Source Agreement (SFP-MSA). As a bidirectional WDM optical transceiver, TL-SM321B-2 uses an integrated LC bidirectional optical interface connector, and the data link is up to 2 km in 9/125 μm SMF (single-mode fibre).
The TL-SM321B-2 also includes the DDM (Digital Diagnostic Monitoring) function, which is compatible with SFF-8472. DDM supports real-time monitoring of the transceiver and displays parameters including transceiver power, transmitting/receiving optical power and operating temperature.
The TL-SM321B-2 from TP-Link is used in practice for fibre optic networks over short and medium distances and provides a fast and stable Gigabit fibre connection for switches, routers, servers, etc.

Package contents
– Package contents: SFP module TL-SM321B-2, installation instructions
Hardware functions
– DDM: Yes
– SFP MSA: Yes
– Hot-swappable: Yes
Media converters and modules
– Standards and protocols: IEEE 802.3z, TCP/IP
– Wavelength: Tx: 1310 nm; Rx: 1550 nm
– Dimensions (WxDxH): 2.2 x 0.6 x 0.5 inches (55.4 x 14.6 x 12.9 mm)
– Power supply: 3.3 V
– Safety and emissions: FCC, CE
– Cable: singlemode fibre
– Fibre type: 9/125 μm singlemode
– Maximum cable length: 2 km
– Data rate: 1.25 Gbps
– Port type: LC Simplex
– Environment: operating temperature: 0-70°C (32-158°F); storage temperature: -40-85°C (-40-185°F); Operating humidity: 10-90% relative humidity, non-condensing; Storage humidity: 5-90% relative humidity, non-condensing