{"product_id":"tp-link-tl-sm321b-2-bidi-sfp-module-1000base-bx","title":"TP-Link TL-SM321B-2 WDM BiDi SFP Module 1000Base-BX 1310\/1550nm","description":"\u003ch2\u003eSingle-Fibre Gigabit Connectivity — Cut Your Fibre Infrastructure in Half\u003c\/h2\u003e\n\n\u003cp\u003eThe TP-Link TL-SM321B-2 is a 1000Base-BX WDM BiDi (Bi-Directional) SFP module that transmits and receives over a single strand of single-mode fibre using an LC simplex connector. By using separate wavelengths for TX (1310nm) and RX (1550nm), it eliminates the need for a second fibre strand per link — halving cabling costs and conduit usage compared to standard dual-fibre SFP modules. Ideal for inter-building links, IP surveillance backbones, and any installation where fibre runs are limited or expensive.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eImportant:\u003c\/strong\u003e The TL-SM321B-2 (TX 1310nm \/ RX 1550nm) must be paired with a \u003cstrong\u003eTL-SM321A-2\u003c\/strong\u003e module (TX 1550nm \/ RX 1310nm) at the opposite end of the fibre link. Two TL-SM321B-2 modules on the same link will not establish a connection.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSingle-Strand BiDi Operation:\u003c\/strong\u003e Transmits and receives over one fibre strand using WDM technology — TX at 1310nm, RX at 1550nm — reducing fibre infrastructure by 50% per link.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLC Simplex Connector:\u003c\/strong\u003e Standard LC simplex interface compatible with widely available single-mode fibre patch leads and infrastructure.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e1.25Gbps Gigabit Data Rate:\u003c\/strong\u003e Full 1000Base-BX Gigabit throughput for switch-to-switch and switch-to-media-converter fibre uplinks.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003e10km Maximum Range:\u003c\/strong\u003e Supports single-mode fibre runs up to 10km — suitable for inter-building and campus network links.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDigital Diagnostic Monitoring (DDM):\u003c\/strong\u003e Real-time monitoring of temperature, voltage, TX power, and RX power via the host switch management interface for proactive fault detection.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHot-Swappable:\u003c\/strong\u003e Insert or remove the module without powering down the host switch — minimising downtime during installation or replacement.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSFP-MSA Compliant:\u003c\/strong\u003e Broad compatibility with TP-Link managed switches and media converters that accept standard SFP modules.\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eLow Power:\u003c\/strong\u003e 3.3V powered directly from the host device — no external power required.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eCommon Use Cases\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eInter-building Gigabit fibre links using a single fibre strand per connection\u003c\/li\u003e\n  \u003cli\u003eIP surveillance switch-to-switch fibre uplinks in large CCTV installations\u003c\/li\u003e\n  \u003cli\u003eConduit-constrained environments where maximising links per fibre count is critical\u003c\/li\u003e\n  \u003cli\u003eCampus and multi-building networks requiring cost-effective single-mode fibre connectivity\u003c\/li\u003e\n  \u003cli\u003eAdding Gigabit fibre uplinks to existing TP-Link managed switches without running additional fibre\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cdiv style=\"overflow-x:auto;\"\u003e\n  \u003ctable style=\"width:100%;border-collapse:collapse;font-size:0.95em;\"\u003e\n    \u003ctbody\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;width:40%;\"\u003eModel\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003eTL-SM321B-2\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eModule Type\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e1000Base-BX WDM BiDi SFP\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eConnector\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003eLC Simplex\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eTX Wavelength\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e1310nm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eRX Wavelength\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e1550nm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eData Rate\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e1.25Gbps (1000Base-BX)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eFibre Type\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e9\/125μm Single-Mode (SMF)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eMax Cable Length\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e10km\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eDDM Support\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eHot-Swappable\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eSFP-MSA Compliant\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eRequired Pair Module\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003eTL-SM321A-2 (TX 1550nm \/ RX 1310nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003ePower Supply\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e3.3V (from host device)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eStandard\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003eIEEE 802.3z, TCP\/IP\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eOperating Temperature\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e0°C to 70°C\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eStorage Temperature\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e-40°C to 85°C\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eOperating Humidity\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e10–90% RH (non-condensing)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eWeight\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003e60g\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f5f5f5;\"\u003e\n\u003ctd style=\"padding:8px 12px;font-weight:600;\"\u003eCertifications\u003c\/td\u003e\n\u003ctd style=\"padding:8px 12px;\"\u003eFCC, CE\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\n\u003ch3\u003eWhat module do I need at the other end of the fibre link?\u003c\/h3\u003e\n\u003cp\u003eThe TL-SM321B-2 (TX 1310nm \/ RX 1550nm) must be paired with a \u003cstrong\u003eTL-SM321A-2\u003c\/strong\u003e module (TX 1550nm \/ RX 1310nm) at the opposite end. Using two TL-SM321B-2 modules on the same link will not establish a connection — the wavelengths must be complementary.\u003c\/p\u003e\n\n\u003ch3\u003eWhy use a BiDi SFP instead of a standard dual-fibre SFP?\u003c\/h3\u003e\n\u003cp\u003eStandard SFP modules use two fibre strands per link (one for TX, one for RX). A BiDi module uses a single strand by splitting TX and RX onto different wavelengths. This halves the fibre count required per link, reducing cabling costs and conduit usage — particularly valuable in installations where fibre runs are expensive or conduit space is limited.\u003c\/p\u003e\n\n\u003ch3\u003eWhat fibre cable is required?\u003c\/h3\u003e\n\u003cp\u003eThe TL-SM321B-2 requires 9\/125μm single-mode fibre with an LC simplex connector on each end. It is not compatible with multi-mode fibre (OM1, OM2, OM3, OM4) or LC duplex patch leads.\u003c\/p\u003e\n\n\u003ch3\u003eWhat does Digital Diagnostic Monitoring (DDM) do?\u003c\/h3\u003e\n\u003cp\u003eDDM allows the host switch to read real-time performance data from the SFP module — including optical TX and RX power levels, temperature, and supply voltage. This helps network administrators detect degraded modules or fibre links before they cause outages. DDM data is viewable via the switch's management interface.\u003c\/p\u003e\n\n\u003ch3\u003eIs it compatible with third-party switches?\u003c\/h3\u003e\n\u003cp\u003eThe TL-SM321B-2 is SFP-MSA compliant, providing broad compatibility. TP-Link validates it specifically for use with TP-Link managed switches and media converters. Compatibility with third-party equipment is not guaranteed — some vendors restrict modules to vendor-coded units only.\u003c\/p\u003e\n\n\u003ch3\u003eCan I hot-swap it without rebooting the switch?\u003c\/h3\u003e\n\u003cp\u003eYes. The TL-SM321B-2 is hot-swappable and can be inserted or removed while the host switch is powered on and running, minimising disruption during installation or replacement.\u003c\/p\u003e","brand":"TP-Link","offers":[{"title":"Default Title","offer_id":43198325555429,"sku":"TL-SM321B-2","price":25.3,"currency_code":"AUD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0637\/1554\/1221\/files\/tp-link-sm321b-2-omada-1000base-bx-wdm-sfp-module.webp?v=1779683030","url":"https:\/\/cctvguru.com.au\/products\/tp-link-tl-sm321b-2-bidi-sfp-module-1000base-bx","provider":"CCTV Guru","version":"1.0","type":"link"}