TP-Link TL-SM321A-2 Gigabit WDM Bi-Directional SFP Module Price in Kenya

The TP-Link TL-SM321A-2 is a short-to-medium-distance 1000Base-BX WDM Bi-Directional SFP module designed for Gigabit Ethernet communication over a single strand of single-mode fibre.

It supports a 1.25Gbps optical data rate, transmits at 1550nm, receives at 1310nm, uses 9/125µm single-mode fibre, and supports distances of up to 2 kilometres. The module uses an LC simplex connector and is designed to work with the complementary TP-Link TL-SM321B-2.

TP-Link also specifies DDM, SFP-MSA compliance and hot-swappable operation, making the TL-SM321A-2 suitable for switches, routers, servers, media converters, CCTV networks and enterprise fibre links. 

TP-Link TL-SM321A-2 Specifications

TP-Link's current SM321A-2 datasheet confirms the 1550nm Tx / 1310nm Rx wavelength pair, 2km maximum reach, 1.25Gbps data rate, LC simplex port, DDM and hot-swappable operation. 

What Is the TP-Link TL-SM321A-2?

The TL-SM321A-2 is an optical SFP transceiver designed to establish a Gigabit Ethernet connection through a single optical fibre strand.

A typical connection is:

Switch A → TL-SM321A-2 → Single Fibre → TL-SM321B-2 → Switch B

The two modules use complementary wavelengths so that traffic can move in both directions over the same fibre.

TP-Link specifically describes the TL-SM321A-2 and TL-SM321B-2 as a paired solution capable of creating a full-duplex Gigabit path over one single-mode fibre for up to 2km. 

What Does WDM Mean?

WDM means:

Wavelength Division Multiplexing

WDM allows more than one optical wavelength to travel over the same fibre.

For the TL-SM321A-2:

Transmit: 1550nm
Receive: 1310nm

For the complementary TL-SM321B-2:

Transmit: 1310nm
Receive: 1550nm

This enables the two modules to communicate simultaneously through a single fibre strand.

What Does Bi-Directional Mean?

A Bi-Directional or BiDi SFP transmits and receives information over one fibre.

A conventional duplex SFP usually needs:

Core 1 → Transmit

Core 2 → Receive

The TL-SM321A-2 uses:

One fibre → Tx + Rx

because the transmit and receive signals use different wavelengths.

1000Base-BX Gigabit Ethernet

The TL-SM321A-2 is based on:

1000Base-BX

This is a Gigabit Ethernet optical architecture designed for bidirectional single-fibre links.

TP-Link explicitly lists the module as a 1000Base-BX WDM Bi-Directional SFP Module.

1.25Gbps Data Rate

The optical transceiver operates at:

1.25Gbps

This supports standard:

1 Gigabit Ethernet

TP-Link lists the module's data rate as 1.25Gbps. 

1550nm Transmit Wavelength

The TL-SM321A-2 transmits at:

1550nm

Its complementary TL-SM321B-2 must therefore receive at 1550nm.

1310nm Receive Wavelength

The module receives at:

1310nm

The TL-SM321B-2 at the opposite end transmits at 1310nm.

Therefore:

Up to 2KM Transmission Distance

The TL-SM321A-2 is specifically designed for fibre links of up to:

2 kilometres / 2,000 metres

using:

9/125µm single-mode fibre. 

This makes it suitable where a 10km or 20km SFP is unnecessary.

Why Use a 2KM BiDi SFP?

A 2km-rated module is useful for links such as:

• Buildings in the same compound

• Office parks

• Schools

• Hospitals

• Factories

• CCTV sites

• Data rooms

• Warehouses

• Enterprise campuses

• Fibre connections within estates

It provides significantly greater distance than copper Ethernet while avoiding the need for longer-range optics where they are unnecessary.

Single-Mode Fibre

The TL-SM321A-2 requires:

9/125µm Single-Mode Fibre

TP-Link identifies this fibre type throughout its current TL-SM321A-2 documentation.

Single-mode fibre is particularly useful for:

• Long campus routes

• Building interconnections

• Outdoor fibre

• Fibre distribution networks

• ISP infrastructure

One Fibre Strand

The module's main design advantage is that it uses only:

1 fibre core

for a full-duplex Gigabit connection.

A matched TL-SM321A-2/TL-SM321B-2 pair can therefore reduce fibre-core consumption compared with conventional duplex SFP modules.

LC Simplex Connector

The TL-SM321A-2 uses:

LC Simplex

TP-Link specifies an integrated LC Bi-Directional optical interface. 

This means a typical installation uses:

LC-LC Simplex Single-Mode Patch Cord

rather than a duplex LC patch cord.

Watch TP-Link TL-SM321A-2 Video

https://youtu.be/PfqJLzF3l6U

The TP-Link TL-SM321A-2 is designed for networks that need reliable Gigabit fibre connectivity without consuming two fibre cores for every connection. Its BiDi architecture sends and receives traffic on different wavelengths through one single-mode fibre.

The 2km transmission distance makes it especially suitable for campus, building-to-building, CCTV and enterprise links where a 10km or 20km transceiver would provide unnecessary excess reach. It gives network designers a more targeted optical solution for short-to-medium-distance fibre infrastructure.

The module also provides DDM support, allowing compatible network equipment to monitor operational parameters including transmit and receive optical power and operating temperature. This can make troubleshooting and preventive maintenance considerably easier. 

Digital Diagnostic Monitoring – DDM

The TL-SM321A-2 supports:

Digital Diagnostic Monitoring

and TP-Link identifies its DDM implementation as compatible with:

SFF-8472. 

Depending on the host device, DDM can provide information such as:

• Tx optical power

• Rx optical power

• Operating temperature

• Module current

• Diagnostic condition

Why DDM Is Useful

DDM can help network technicians identify:

• Low optical power

• High link loss

• Fibre connector problems

• Poor splices

• Fibre damage

• High transceiver temperature

It is especially useful in managed enterprise and ISP networks.

SFP-MSA Compatibility

The TL-SM321A-2 supports:

SFP-MSA

TP-Link states that the module is developed according to the Small Form Pluggable Multi-Source Agreement. 

This defines the physical and electrical interface of the SFP.

Host-device compatibility should still be checked.

Hot-Swappable Design

The module supports:

Hot Swappable

operation.

This makes replacement and maintenance easier because the entire network switch does not need to be replaced when an optical module is changed.

TP-Link TL-SM321A-2 and TL-SM321B-2 Pair

The correct complementary pair is:

TL-SM321A-2 ↔ TL-SM321B-2

TP-Link specifically identifies the B-2 module as the matching partner. 

A typical link is:

Switch / Router
↓
TL-SM321A-2
↓
Single OS2 Fibre Core
↓
TL-SM321B-2
↓
Switch / Router

Can Two TL-SM321A-2 Modules Work Together?

Normally, no.

Two A-2 modules would both:

• Transmit at 1550nm

• Receive at 1310nm

This means the wavelength assignments do not match.

The correct pairing is:

A-2 + B-2

not:

A-2 + A-2

TP-Link TL-SM321A-2 for Switch-to-Switch Links

The module can connect compatible Gigabit SFP switches over single-mode fibre.

Typical topology:

Access Switch → TL-SM321A-2 → Fibre → TL-SM321B-2 → Core Switch

This is suitable for:

• Enterprise networks

• CCTV networks

• Schools

• Hospitals

• Campuses

• Warehouses

• Factories

TL-SM321A-2 for Building-to-Building Fibre

The 2km range makes this module particularly suitable for connecting buildings within a common compound.

Example:

Administration Building
↓
Switch + TL-SM321A-2
↓
Single Fibre
↓
Switch + TL-SM321B-2
↓
Remote Building

TL-SM321A-2 for CCTV

A typical CCTV application is:

IP Cameras → PoE Switch → TL-SM321A-2 → Single Fibre → TL-SM321B-2 → Core Switch/NVR

This configuration is useful where camera installations span large premises.

TL-SM321A-2 for Campus Networks

The module is suitable for:

• Universities

• Colleges

• Schools

• Hospitals

• Hotels

• Government facilities

• Industrial sites

The single-fibre architecture can also preserve spare cores for future network expansion.

TL-SM321A-2 for Enterprise Networks

Businesses can use the module for:

• Floor-to-floor links

• Building uplinks

• Remote server rooms

• Network cabinets

• Warehouse links

• CCTV backbones

• Data distribution

TL-SM321A-2 vs TL-SM321B-2

TL-SM321A-2 vs TL-SM321A

The key difference is transmission distance.

The A-2 version is designed specifically for shorter links.

TP-Link's older TL-SM321A documentation shows the same 1550nm Tx / 1310nm Rx architecture but with longer-distance variants. 

TL-SM321A-2 vs TL-SM311LS

TL-SM321A-2 vs TL-SM311LM

TL-SM321A-2 vs 20KM BiDi SFP

Using a 2km-rated module can be more appropriate when the physical route is short.

Why Not Always Use a 20KM SFP?

Long-range optical modules are not automatically the best solution for short networks.

The correct SFP should be selected according to:

• Fibre distance

• Optical power budget

• Receiver sensitivity

• Connector losses

• Network topology

Using a module designed for the intended distance provides a more controlled optical design.

Fibre Core Saving

Suppose a cable has eight usable single-mode cores.

With conventional duplex SFP links:

8 cores ÷ 2 = 4 links

Using BiDi links:

8 cores = potentially 8 independent fibre links

This is one of the major benefits of the TL-SM321A-2/TL-SM321B-2 architecture.

Optical Budget

Even though the product is rated for 2km, the total link loss must remain within its optical specifications.

Loss comes from:

• Fibre attenuation

• Connectors

• Adapters

• Fusion splices

• Patch cords

• Fibre bends

• Connector contamination

Testing the Fibre Link

Optical Power Meter

An Optical Power Meter can help measure received optical power.

OTDR

An OTDR can identify:

• Fibre distance

• Fibre breaks

• Poor splices

• Reflective connectors

• Macrobends

• High attenuation

VFL

A Visual Fault Locator can help with basic fibre continuity and visible fault identification.

Cleaning LC Connectors

The LC connector should be cleaned before connection.

Contamination can cause:

• Excessive optical loss

• Link failure

• Low Rx readings

• Intermittent connectivity

• Packet errors

Maximum Laser Output

TP-Link's current SM321A-2 datasheet lists:

0.501mW (-3dBm)

as the maximum laser output power. 

This figure applies to that current datasheet version and should not automatically be generalized to every older revision.

Operating Temperature

The module is specified for:

0°C to 70°C operating temperature

and approximately:

-40°C to 85°C storage temperature. 

Dimensions

The current SM321A-2 datasheet specifies approximately:

55.4 × 13.7 × 12.9mm. 

Some regional TL-SM321A-2 pages list approximately 55.4 × 14.6 × 12.9mm, reflecting revision differences. 

TP-Link TL-SM321A-2 Price in Kenya

The TP-Link TL-SM321A-2 price in Kenya can vary according to:

• Distributor

• Hardware revision

• Stock availability

• Warranty

• VAT

• Import cost

• Quantity ordered

• Whether it is supplied individually or with the TL-SM321B-2

The product is also marked End of Life on TP-Link's US page, while it remains listed in several other TP-Link regional catalogs, so local availability may vary significantly. 

Contact Fiber Optics Kenya for the current TL-SM321A-2 price and availability in Kenya.

Is TL-SM321B-2 Included?

Normally, the TL-SM321A-2 package contains:

• TL-SM321A-2 module

• Installation guide

The complementary TL-SM321B-2 is generally a separate module. 

Before purchasing, confirm whether the quoted price is for:

One module

or

A complete TL-SM321A-2 + TL-SM321B-2 pair.

How to Choose the Correct TL-SM321A-2

Before buying, verify:

1. Your network requires Gigabit Ethernet.

2. The equipment has a compatible SFP port.

3. The installed fibre is 9/125µm single mode.

4. You want to use one fibre strand.

5. The route is within approximately 2km.

6. The opposite end uses TL-SM321B-2.

7. The connector is LC simplex.

8. DDM is supported if optical monitoring is required.

Recommended Accessories

Frequently Asked Questions About TP-Link TL-SM321A-2

What is the TP-Link TL-SM321A-2?

It is a 1000Base-BX WDM Bi-Directional Gigabit SFP module.

What is its data rate?

1.25Gbps. 

Is it a Gigabit SFP?

Yes.

What wavelength does it transmit?

1550nm. 

What wavelength does it receive?

1310nm. 

What fibre does it use?

9/125µm single-mode fibre.

How far can TL-SM321A-2 transmit?

Up to approximately 2km. 

How many fibre cores does it require?

One.

Is it BiDi?

Yes.

What does BiDi mean?

Bi-Directional fibre communication using a single fibre strand.

What does WDM mean?

Wavelength Division Multiplexing.

What connector does it use?

LC Simplex. 

Does it use LC duplex?

No.

Which module pairs with TL-SM321A-2?

TL-SM321B-2. 

Can two TL-SM321A-2 modules connect directly?

Normally no. Their wavelength assignments are the same rather than complementary.

Can TL-SM321A-2 connect to TL-SM321B-2?

Yes. That is the intended pair.

Is TL-SM321A-2 the same as TL-SM321A?

No. TL-SM321A-2 is specifically designed for a 2km link.

Is TL-SM321A-2 a 20km SFP?

No.

Can it work over 500 metres?

Yes, provided the optical link remains within specification.

Can it work over 1km?

Yes.

Can it work over 2km?

Yes, subject to total optical loss.

Can it work over 5km?

It is not rated for 5km. Use an appropriate longer-distance module.

Can it work over 10km?

No. Choose a 10km or longer-rated BiDi module.

Can it work over 20km?

No. Use a 20km BiDi pair.

Does it support DDM?

Yes. 

What DDM standard does it support?

TP-Link states compatibility with SFF-8472. 

Is it SFP-MSA compatible?

Yes. 

Is it hot-swappable?

Yes. 

What voltage does it use?

3.3V. 

Is it single mode?

Yes.

Can I use multimode fibre?

It is designed for 9/125µm single-mode fibre.

Can I use OS2 fibre?

Yes.

Can it connect two switches?

Yes, with compatible equipment and the correct complementary module.

Can it connect buildings?

Yes.

Is it suitable for campus networks?

Yes.

Is it suitable for CCTV?

Yes.

Is it suitable for enterprise networks?

Yes.

Is it suitable for schools?

Yes.

Is it suitable for hospitals?

Yes.

Is it suitable for factories?

Yes.

Is it suitable for ISP networks?

It can be used for appropriate point-to-point Gigabit links.

Is it an EPON SFP?

No.

Is it a GPON SFP?

No.

Can it replace an EPON PX20 module?

No.

Is it a 10G SFP+?

No.

Can it transmit 10Gbps?

No. It is a 1Gbps Ethernet module.

Can I use LC-LC simplex fibre?

Yes.

Can I use LC-SC simplex fibre?

Yes, if the remote termination and connector polish are compatible.

Do I need a duplex patch cord?

No.

Should I clean the fibre connector before installation?

Yes.

Can dirty connectors cause link failure?

Yes.

Can I test it with an Optical Power Meter?

Yes.

Can I test the fibre with an OTDR?

Yes.

What is its operating temperature?

0°C to 70°C. 

What is its storage temperature?

Approximately -40°C to 85°C.

What is the maximum laser output?

The current datasheet specifies 0.501mW (-3dBm). 

Is the TL-SM321A-2 discontinued?

TP-Link's US page marks it End of Life, although other regional TP-Link sites continue to list the product, so availability depends on market and stock. 

What is the TL-SM321A-2 price in Kenya?

Pricing depends on supplier, stock, hardware revision and import availability. Contact Fiber Optics Kenya for a current quote.

Is TL-SM321B-2 included?

Normally no. It is generally purchased separately.

Do you supply TL-SM321A-2 and TL-SM321B-2 pairs?

Yes, subject to stock availability.

Do you supply longer-range BiDi SFPs?

Yes.

Do you supply LC simplex patch cords?

Yes.

Do you supply single-mode fibre?

Yes.

Do you supply media converters?

Yes.

Do you supply Optical Power Meters?

Yes.

Do you supply OTDRs?

Yes.

Can businesses order SFPs in bulk?

Yes. Bulk orders are suitable for fibre contractors, enterprises, CCTV installers, campuses and ISPs.

Do you deliver outside Nairobi?

Yes. Fiber Optics Kenya supplies fibre optic and networking equipment throughout Kenya.

Why Buy TP-Link TL-SM321A-2 from Fiber Optics Kenya?

Contact Fiber Optics Kenya

Fiber Optics Kenya
Lyric House, 7th Floor Room S9
Kimathi Street, Nairobi

Phone: +254 704 991 492
Email: info@fibreopticskenya.co.ke

The TP-Link TL-SM321A-2 Gigabit WDM Bi-Directional SFP Module is designed for efficient Gigabit Ethernet transmission over one 9/125µm single-mode fibre strand. It supports 1.25Gbps, Tx1550nm/Rx1310nm, LC simplex connectivity, DDM, SFP-MSA and hot-swappable operation, with a maximum rated transmission distance of approximately 2km. 

When paired with the complementary TL-SM321B-2, the module creates a full-duplex Gigabit connection using a single fibre core, making it especially useful for campus networks, enterprise buildings, CCTV systems, schools, hospitals, warehouses and short-to-medium-distance fibre links. 

Contact Fiber Optics Kenya for the current TP-Link TL-SM321A-2 price in Kenya, TL-SM321A-2/TL-SM321B-2 pairs, longer-range BiDi SFP modules, LC simplex patch cords, media converters, fibre testing equipment, bulk orders and nationwide delivery.