transceivers for qsfp28 to sfp28 in 2021

Many people are searching for solutions that will enable them to interface qsfp28 to sfp28. One popular method you can use to achieve this goal is to use a qsfp28 to sfp28 adapter. You could also use a qsfp28 breakout cable from QSFPTEK. The qsfp28 to sfp28 adapter can enable you to migrate to 100 gigabit ethernet.

The big question on peoples’ minds is, “isn’t it better to buy a breakout or fanout cable?” What more benefits will a qsfp28 to sfp28 adapter give me? We will answer those questions and more shortly.

Qsfp28 to Sfp28 Adapter – Is It The Magic Bullet?

QSFP28 Adapter
QSFP28 Adapter

The adapter is a qsfp28 module that has a receptacle for connecting sfp28 connectors at the back. The adapter acts as a middleman between qsfp28 and sfp28 cables. You can connect an sfp28 module to this adapter and connect the adapter to a qsfp28 port to enable the transition between the two speeds.

This adapter is the best way to convert a qsfp28 port to accept sfp28 cables. Also, the adapter has an EEPROM id that enables you to connect the adapter to switches of various companies.

Unlike the operating temperature of common optical transceivers, the Qsa28 adapter can work in high-temperature servers. The operating temperature of this module is between -10 degrees and 85 degrees centigrade. This is a much wider temperature range than optical transceivers support.

Another benefit of the qsfp28 to sfp28 adapter is that it does not cause extra latency. It is because of the lack of signal processing that this adapter doesn’t add any delay in the signal.

The adapter can work in many ports including Qsfp28, qsfp dd, qsfp+, and qsfp56. You can also connect it to many types of cables including the SR sfp multimode cable, sfp multimode AOC cable, the lr sfp single-mode cable, and the base-t sfp converter.

Why Not Use A Breakout Cable Instead Of The Qsfp28 to Sfp28 Adapter?

The qsfp28 to sfp+ breakout cable is a cable with a qsfp28 connector on one end that splits into four sfp+ connectors on the opposite end. The breakout cable uses duplex serial connections to enable two-way communication on all four sfp+ ports. The breakout cable is a short-distance connector best suited for use within the same rack.

So, why not skip the qsfp28 to sfp28 adapter and use a breakout cable instead. Let us compare the two alternatives to determine the one best suited for the job. The key areas we will look at include performance, cost, and compatibility.

Qsfp28 to Sfp28 Adapter Cost

The qsfp28 to sfp28 adapter does not conform to the Multi-source Agreement (MSA). Only one company owns patent rights to this adapter. Because of this monopoly, the company charges other vendors a lot of money for the rights to produce the adapter. A qsfp28 breakout cable complies with the MSA standard. That means several manufacturers have permission to make the cable. The cable works with devices from other companies so long as they meet MSA standards.

The takeaway here is that the qsfp28 to sfp28 adapter is a lot more expensive than the qsfp28 breakout cable from QSFPTEK.

100G to 25G break out cable
100G to 25G break out cable

Qsfp28 to Sfp28 Adapter Performance

The adapter gives you the flexibility to connect any sfp28 connector to a 100Gb sfp port. The issue people have with the QSA28 adapter is that it currently supports 25G-100G speed. It means that when you use this adapter, you will downgrade the connection from 100 Gbps to 25 Gbps. You will not harness the extra 75 Gbps bandwidth when you use the qsfp28 to sfp28 adapter.

The breakout cable does not have this limitation. You can split a 100 Gbps connection into four 25 Gbps cables that work at full speed.

Qsfp28 To Sfp28 Adapter Compatibility

Because of the lack of MSA standard support, using a qsfp28 to sfp28 adapter will be hit and miss. It is because manufacturers of devices like switches and routers do not have to support the adapter. Some manufacturers break support with generic optical modules.

Power Consumption Of Qsfp28 to Sfp28 Adapter

The QSA28 adapter is a passive device. It receives the signal from the sfp28 module and passes it to the qsfp28 port. Since the adapter does not process the signal, it does not consume any power. A breakout cable consumes power to work.

Things To Keep In Mind About The Adapters and Breakout Cable

  • To ensure the connection between the qsfp28 port and sfp28 connector works, you must enable fanout mode on the host device. You should also know that not all devices support fanout mode, so consult the manual.
  • You can connect an sfp28 module to a qsfp28 port using the adapter. But, you cannot connect a qsfp28 module into an sfp28 port.
  • The communication industry is quickly changing. Sometimes it will be cheaper to buy high-speed equipment to be able to keep up with the changing market rather than resorting to intermediary measures.
  • The technology behind qsfp28 to sfp28 breakout cables has advanced rapidly. Thus, the breakout cables are guaranteed to work on any host device. Even if a host device manufacturer uses vendor lock-in, a compatible breakout cable from QSFPTEK will work on the device.


If you are migrating from a 100g port to 25g connections, you can use either the breakout cable or adapter. However, after considering the performance of the cables, compatibility across host devices, and cost, there is only one winner. The breakout cable comes out on top regardless of the challenge.

You can use the qsfp28 to sfp28 adapter as an intermediate step before installing breakout cables. There is a big probability that you will need to recover the unused capacity that is created when using an adapter. QSFPTEK has a very high-quality qsfp28 to sfp28 breakout cable that works with many host devices. It is also very affordable compared to other brands. The quality of their cables is second to none. To get your hands on the best value breakout cable send an email to

Which Qsfp28 Transceiver Should You Choose And Why?


For any network engineer who wants to create a high-performance 100G network, the qsfp28 transceiver has become indispensable. The versatility of a 100g qsfp28 makes it a no-brainer because it complies with the 100Gbps ethernet standard as well as InfiniBand EDR specification. The qsfp 100g transceiver also works with devices from various manufacturers like Huawei, Cisco, and HPE. Let’s now break down the reasons why the 100g qsfp28 is now the go-to for people looking for low-powered, small-footprint transceivers.

Qsfp28 Transceiver Types And Supported Standards

There have been many challenges that have faced developers of high-speed 100G transceivers. This has led to many great devices gaining popularity and shortly afterward fading away because of the inability to meet certain industry requirements. However, the qsfp28 transceiver has become a constant feature of high-speed 100G networks. This is partly due to its numerous use cases, small form factor, and acceptable power requirements.

The 100g qsfp28 transceiver family is huge and one of the features that distinguish various iterations is transmission mode. There are broadly four categories including single-mode, multi-mode transceivers, active optical cable (AOC) and direct attach cable (DAC). Amongst the affordable connectivity options is multi-mode, Active Optical Cable, and DAC transceivers. However, this comes at a cost of transmission distance because they are only good up to 100 meters. Single-mode cables are costlier but can move data much further as can be seen in deployments using qsfp 100g er4 s.

There are as well many versions of the 100g qsfp28 transceiver module as we shall now find out.

The common types of qsfp28(including sr4,lr4,er4,zr4)
The common types of qsfp28

Short- to medium-haul qsfp28 transceiver types

Qsfp 100g sr4: Back To Basics

This is not a single brand but rather a networking standard developed by IEEE. The 100Ggbase sr4 transceiver makes use of 8 fibers in multi-mode configuration for transmitting data bi-directionally over the 850nm spectrum. The 100g qsfp28 sr4 can transmit data up to 70 meters over the OM3 interface and up to 100 meters OM4 when the selected interface is MTP. The ideal connectivity solution for these modules is 12-fiber OM3/4 cables using MTP.

Qsfp 100g lr4: Going The Distance

The distance challenge has always existed when it comes to networking capabilities. To improve over the previous transceiver model, the IEEE published the 100G qsfp28 lr4 standard. This iteration is primarily concerned with increasing the range of transmission beyond 100 meters and it is rated for up to a 10-kilometer transmission distance. It achieves this with the fiber optic link in single-mode. To achieve this the 100gbase lr4 uses four wavelengths in the 1310nm range to transmit data. It also uses WDM as well as a duplex LC interface to increase transmission efficiency.

Intermediate-range qsfp28 transceiver modules

Apart from the above-mentioned modules, there are several other transceivers ideal for short-distance deployments. One noteworthy module is the 100G qsfp28 DAC which is the most cost-effective option for deployments not exceeding 5 meters. This module has two main direct attach cables including qsfp28 to sfp28 DAC and qsfp28 to qsfp28 DAC.

For slightly longer transmission, the 100g qsfp28 psm4 can move data up to 500 meters with single-mode fiber using the MTP interface. The benefit of this module is that it is a lot more affordable compared to the 100G base lr4 module. For transferring data up to 2 kilometers, the 100g qsfp28 cwdm4 is ideal.

Long-haul Qsfp28 Transceiver Options

Many companies require to transmit data over very long distances. Two mainstream transceivers can fulfill these requirements. The first one is the qsfp28 er4 which uses single-mode fiber to transmit data up to 30 kilometers. When coupled with FEC it can send data over 40 km with normal LC connectors.

The second alternative is the very long-distance qsfp28 zr4 which uses single-mode fiber as well. This module is equipped with a duplex LC connector and transmits over the 1310 nm wavelength. Its transmission distance can reach to 80km.

ApplicationData CenterData CenterDCIDCI、Metro

Factors to consider when choosing qsfp28 transceiver

For a while now, the gold standard for 100-gigabit ethernet connectivity is the qsfp28 transceiver. However, several modules comply with this standard. So, which product should a network engineer use for their particular deployment? To answer that, several factors come into play as we shall now delve into.

Cabling Distance

When the transmission distance is short (below 5 meters), a network can be easily served with a passive direct attach cable. These include qsfp28 to 4xsfp28 as well as qsfp28-qsfp28 direct attach cables. Due to the short transmission distance, these DAC’s comfortably do the job of 100g optical modules without sacrificing performance. As an added benefit, the DAC option comes in cheaper than the optical 100g qsfp28 transceiver. The passive qsfp28 DAC cables are excellent for distances between 1 and 5 meters.

QSFP28 to SFP28 passive DAC | QSFPTEK
QSFP28 to SFP28 passive DAC | QSFPTEK

Multi-mode Cables Between Switches

For 100-gigabit ethernet networks using multi-mode fiber to connect switches, there are two possibilities. The first option is suitable for cables running between 3 and 20 meters and it is the qsfp28 active optical cable. The second possibility is the 100g qsfp28 sr4 optical module attached to a 12-pin patch cord with either OM3/4 interface. In this type of setup, data can be transmitted up to 100 meters.

Single-mode Cables Between Switches

Transmission distance is the single biggest differentiator between various 100g qsfp28 modules. The intermediate distance of between 100m and 2km is most relevant for large data centers. At this distance, cost-effectiveness is key and that is where the qsfp28 CRL4/CWDM4, as well as qsfp28 psm4 modules, come into play. Under 500 meters, the best option is the PSM4 when coupled with 8 single-mode cables in parallel. To reach two kilometers, the CRL4 coupled with single-mode optic cable strikes the perfect balance between performance and cost while maintaining high reliability.


Long-distance Single Mode Optic Fiber

To create even longer 100G connections, a more capable qsfp28 transceiver is required. According to IEEE standards, the ideal transceiver for the job is the 100gbase-lr4 module that has an LC interface. This setup is suitable for networks spanning up to 10 kilometers.

Despite the numerous types of transceiver modules for short- to long-haul Ethernet networks, optical fiber cables are indispensable. High-speed cables are ideal to save cost for shorter distances but optical cables reign supreme for longer distances. QSFPTEK can offer all the above types of 100g transceivers. If you have any questions about transceivers, you can always get in touch with QSFPTEK.Inc staff via