# SFP Fiber Transceiver TP-LINK ISM321B-20, WDM Bi-Directional, 20 km, 1.25Gb, LC (UPC), SMF

**URL:** https://aio.lv/en/product--tp-link-ism321b-20--11545913
**Data updated:** 2026-01-21 13:42 (EET)
**Category:** Network Switches
**Manufacturer:** TP-LINK
**Manufacturer code:** ISM321B-20
**EAN:** 1210002602013
**Warranty:** 5 Years
**Availability:** Available for order
**Price:** 25.49 €
**Prices and availability valid until:** 2026-07-11 23:59
**Price without VAT (21%):** 21.07 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--tp-link-ism321b-20--11545913

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | Tuesday | free |
| Pickup points | 19.06.2026 | 1.99 EUR |
| Courier delivery to door | 19.06.2026 | 4.99 EUR |

## Summary description

Hot-pluggable TP-LINK ISM321B-20 SFP fiber transceiver for single-mode networks, supporting bi-directional WDM transmission up to 20 km. Provides 1.25 Gb/s (IEEE 802.3z) over 9/125 µm SMF with LC (UPC) connector. Operates from 3.3 V, wide temperature range −40 to 85 °C, compact SFP form factor (56.4 × 13.4 × 11 mm). Ideal for extending Ethernet links between switches and routers in campus, ISP or enterprise environments.

## Long description

TP-LINK ISM321B-20 is a hot-pluggable SFP fiber transceiver designed for single-mode (SMF) Ethernet links. It supports bi-directional WDM transmission at 1.25 Gb/s (IEEE 802.3z) over a maximum distance of 20 km using a LC (UPC) connector and 9/125 µm fiber. The module runs from a 3.3 V supply and operates across a wide temperature range, packaged in a compact SFP form factor (56.4 × 13.4 × 11 mm).
Advantages
The transceiver is hot-swappable for easy maintenance and replacement without powering down network equipment. Its single-mode fiber design with LC (UPC) connector and WDM bi-directional capability reduces cabling complexity while supporting long-distance links up to 20 km. The module’s compact SFP dimensions and broad operating temperature range make it suitable for varied installation environments.
Suitable for
Extending Ethernet links between switches and routers in campus networks
Long-distance fiber connections for ISPs and service providers
Enterprise backbone and data center uplinks
Key specifications
Form factor: SFP (small form-factor pluggable)
Data rate: 1.25 Gb/s (1250 Mbit/s, IEEE 802.3z)
Transmission type: WDM bi-directional
Maximum reach: 20 km
Fiber type: Single-mode fiber (9/125 µm)
Connector: LC (UPC)
Interface: Fiber optic SFP
Operating voltage: 3.3 V
Operating temperature range: -40 to 85 °C
Relative humidity (operating/storage): 5–85%
Dimensions (W×D×H): 56.4 × 13.4 × 11 mm
How to use
Insert the TP-LINK ISM321B-20 SFP transceiver into an SFP slot on a compatible switch, router or transceiver cage while the device is powered on if hot-plugging is supported. Connect single-mode LC fiber cables (9/125 µm) to the LC (UPC) connector, ensuring correct polarity for bi-directional WDM links. Verify link status through the host device’s interface and monitor for optical levels and alarms per network management tools.
Usage recommendations
For reliable operation, use quality single-mode fiber (9/125 µm) with LC (UPC) connectors and adhere to proper cleaning procedures before connection. Match transceiver wavelength and WDM pair correctly at both ends and observe manufacturer guidelines for ESD protection during handling and installation.

## FAQ

### How much does the SFP Fiber Transceiver TP-LINK ISM321B-20 cost, and is it available for purchase?

The price is 25.49 € (valid at the time of publication and already includes all taxes). The item is available for order — 20 pcs. are in stock, and you can place your purchase right now with delivery across Latvia and Europe or choose pickup at the Riga collection point. We offer favorable purchase terms, including the option to split the payment into convenient monthly installments. Availability and price are updated in real time, so we recommend placing your order in advance.

### If I order this product today, when will I receive my order?

If you place your order today, delivery will be as fast and convenient as possible. You will be able to pick up your order on Tuesday at the Riga pickup point or choose delivery across Latvia and Europe. We carefully inspect every purchase and pack it securely for safe transportation.

### What payment options are available?

AiO.lv offers several payment methods: Bank transfer, Bank cards on-line, Apple Pay, Google Pay. All transactions are 100% secure and encrypted.

### Can this product be purchased for a company (with VAT)?

Yes. AiO.lv works with legal entities in Latvia and across Europe. The product price already includes VAT. For certain product categories, as well as for companies from other EU countries with a valid VAT number, a 0% VAT rate may apply. We issue the invoice immediately after the order is placed, support electronic BIS invoices, and automatically generate all necessary accounting documents. You can complete the purchase for a company online — simply select the company profile and choose bank transfer as the payment method during checkout.

### What is the warranty period?

All TP-LINK products come with an official 2 Years warranty. It covers all manufacturing defects and malfunctions that may occur during use. The warranty is valid at all authorized TP-LINK service centers and through AiO.lv

### Can the product be returned after purchase?

Yes, you can return the product within 14 days of purchase if you bought it as a consumer (not a legal entity). Returns are possible without giving any reason — the main condition is that the product retains its original appearance and full set of accessories. We will make the process as simple and convenient as possible: just contact our customer support team, and we will help you arrange the return.

### Where should I contact for warranty service?

For warranty-related questions you can contact the AiO.lv (SIA VSPRO) customer support team. More information about warranty service: https://aio.lv/en/warranty

## Image

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