Monthly Archives: August 2018

Half Duplex vs Full Duplex: What Are They

Half duplex and full duplex are two communication channels in telecommunications and computer networks. These communication channels provide a way to convey information. The communication channel can be a physical transmission medium or a logical connection on the multiplexing medium. Physical transmission medium refers to substances that can propagate energy waves, such as lines in data communication. Logical connections usually refer to circuit switched connections or group mode virtual circuit connections, such as radio channels. With the help of communication channels, information can be transmitted smoothly. In this article: Half Duplex vs Full Duplex: What Are They, we will discuss half duplex and full duplex.

Duplex Fiber Optic Adapter

Figure 1: Duplex Fiber Optic Adapter

Half Duplex vs Full Duplex: What Are They

We can note that half duplex and full duplex are duplex. Duplex products are very common, only in optical fiber communication products, and in terms of connectors, there are many kinds of duplex connectors, such as SC duplex connectors and LC duplex connectors. So what are half duplex and full duplex? What specific differences do they have?

Full Duplex

First, let’s focus on full duplex. Full duplex data transmission means that data can be transmitted in both directions at the same time. For example, in a LAN with full duplex transmission technology, one workstation can send data over the wire while another workstation is receiving data. Full duplex transmission must mean two-way lines (which can move data in two directions).

half duplex vs full duplex: full duplex

Figure 2: Full Duplex

Half Duplex

Just like the full duplex data transmission we mentioned above, half duplex data transmission also means a two-way line that can transmit data in both directions. However half duplex data transmission refers that data can be transmitted in both directions on the signal carrier, but not simultaneously. For instance, on a LAN using a half duplex transmission technology, a workstation can send data over a line and immediately receive data on the line from the same direction in which the data has just been transmitted.

half duplex vs full duplex: half duplex

Figure 3: Half Duplex

Half Duplex vs Full Duplex: What Are the Differences?

  • 1) In half duplex, both transmitter and receiver can send signals, but only one signal is sent at a time. The walkie-talkie is an example of half duplex communication. While, in full duplex, transmitter and receiver can send signals simultaneously. The telephone is an example of full duplex.
  • 2) In half duplex mode, both devices connected to the link can transmit signals, but only one device can be transmitted at a time. In full duplex mode, all devices on the link can be transmitted at the same time.
  • 3) The performance of full duplex is better than half duplex, because it makes better use of bandwidth than half duplex.

Conclusion

The concept of communication channel plays a key role in understanding the operation of network. Half duplex and full duplex are two communication channel modes. Each of them can be deployed for different applications. It is more cost-effective to choose the right optical cable according to its channel mode. FS.COM has many good duplex products at logical price. If you have any other questions about the topic: half duplex vs full duplex or if you have need of high quality duplex products, please visit www.fs.com.

Understanding 1000BASE-LX SFP and 1000BASE-LH SFP

As the industry of optical communication develops rapidly, the design of optical fiber transceiver is more and more diversified, so as to meet the needs of Gigabit Ethernet. Therefore, various types of mini GBIC (SFP, Small Form-factor Pluggable) and SFP+ emerged. Gradually, we always see 1000BASE-LX SFP and 1000BASE-LH SFP on many websites. However, many people are puzzled about them. Are they similar or different? If they are different, about 1000BASE SFP LX vs LH: what is the difference between them?

SFP LX vs LH: 1000BASE-LX SFP

1000BASE-LX SFP

SFP LX vs LH: What Are They?

If you want to understand 1000BASE-LX SFP and 1000BASE-LH SFP, you first need to understand what Ethernet is. Ethernet was the result of research done at Xerox PARC in the early 1970s, and it later developed into a widely implemented physical and link layer protocol. Fast Ethernet increased from 10 to 100 megabits per second. Gigabit Ethernet was the next iteration, whose speed was increased to 1000 megabits per second. The initial standard for Gigabit Ethernet was produced by the IEEE in June 1998 as IEEE 802.3z, which is often referred to as “1000BASE-X”. 1000 BASE-X is used in industry and refers to Gigabit Ethernet transmission through fiber optics, including 1000BASE-SX, 1000BASE-LX10, 1000BASE-BX10 and our today’s topic 1000BASE-LX.

1000BASE-LX SFP

The rate of 1000BASE-LX SFP is as high as 1.25Gbp/s, and the wavelength of long wavelength laser is 1270nm to 1355nm. LX SFP can be used in single mode and multimode systems, which makes them have some advantages in multimode applications. Although LX SFP is designated to transmit up to 5 kilometers of data over a single mode fiber, it also supports multimode fiber systems with a maximum distance of 550 meters. It is noteworthy that for a distance of more than 330 meters in a multimode fiber, a special transmit-modulated patch cord is needed to reduce the differential mode delay effect.

1000BASE-LH SFP

LH means longer distance. 1000BASE-LH also refers to Gigabit Ethernet transmission. The wavelength of 1000BASE-LH SFP is 1310 microns, and the transmission distance is between 25 km and 70 km. However, 1000BASE-LH is only a term widely used by many suppliers.

SFP LX vs LH: What’s the Difference?

Both 1000BASE-LX and 1000BASE-LH refer to Gigabit Ethernet transmission. Between them, just like mentioned above, 1000BASE-LX is the standard stipulated of IEEE 802.3. It uses long wavelength lasers. While 1000BASE-LH is only a term widely used by many suppliers. Besides, LH means longer distance, while LX (long wavelength) means shorter energy, which is obviously shorter distance. The 1000BASE-LX SFP module compatible with the IEEE 802.3z 1000BASE-LX standard, it can achieve a distance of 10 km over a single-mode fiber. Unlike the 1000BASE-LX SFP module, 1000BASE-LH SFP module can operate at a distance up to 70km over single mode fiber.

Does 1000BASE-LX SFP Work with 1000BASE-LH SFP?

1000BASE-LX SFP and 1000BASE-LH SFP are the most commonly used components in Gigabit Ethernet applications. Here comes a little question: Does 1000BASE-LX SFP work with 1000BASE-LH SFP? The answer is: Yes, 1000 BASE-LX SFP can work with 1000 BASE-LH SFP. For example, Cisco 1000 BASE LX/LH SFP is either made for single mode (long distance) or multimode (short distance). But this module can also be used for both single mode and multimode. In additional, as there are so many types on the market, careful attention should be paid to the distance and price differences between multimode and single mode fibers.

Conclusion

To sum up, about the topic “1000BASE SFP LX vs LH”, we can conclude that: 1000BASE-LX and 1000BASE-LH both refer to Gigabit Ethernet transmission; between them, 1000BASE-LX is a standard, 1000BASE-LH is the term widely used by suppliers. FS.COM offers a wide range of 1000BASE-LX/LH SFP transceiver modules which are compatible with major brands, like Cisco, Juniper, Dell, Brocade, etc. Our optical transceivers are able to fulfill enterprises, service providers, telecom operators and SAN providers to build and fulfill their existing and future network expansions. If you have any need, please contact us.