Applications of Serial Transmission and Parallel Transmission in Network

In the age of the Internet, we are not unfamiliar with data communication, which refers to the process of transferring data signals between two or more devices. Basically, there are two methods used to transmit data signals: serial transmission and parallel transmission. To put it simply, serial transmission sends data bits one after another over a single channel, while parallel transmission sends multiple data bits at the same time over multiple channels. Both of them are commonly used in network applications and this article will focus on applications of serial transmission and parallel transmission in network.

serial transmission and parallel transmission

Application of Serial Transmission

As in serial transmission, bits are sent sequentially on the same channel (wire), one bit at a time, the cost for wires is low but the speed of transmission is slow. In 10G network, serial transmission is usually utilized. For example, a duplex LC fiber that consists of one fiber for transmitting 10G data signals and one fiber for receiving 10G data signals is typically used to completer the data link. In high-density network applications, it is easy to find LC duplex patch cables deployed to connect different network devices.

serial transmission for 10G network

Application of Parallel Transmission

In parallel transmission, multiple bits (usually 8 bits or a byte/character) are sent on different channels (wires, channels) simultaneously over the same cable. Compared with serial transmission, parallel transmission has a faster bit rate, and the higher cost since multiple wires cost more than one single wire. Parallel transmission is usually used in 40G and 100G network because it can transfer more data signals and achieve higher speeds. For example, MTP trunk cable, terminated with MTP/MPO fiber connector on each end, can be used to achieve the connectivity. In 40G networking applications, a 12-fiber MTP fiber connector is used: 10G is sent along each channel or fiber strand in a transmit and receive direction, and 8 of the 12 fibers are used to provide 40G parallel transmission; in 100G network applications, a 24-fiber MTP fiber connector is used: 10G is sent along each channel or fiber strand in a transmit and receive direction, and 20 of the 24 fibers are used to provide 100G parallel transmission.

parallel transmission for 40G network

Note: Parallel transmission can also be applied to 25G duplex fiber pairs to reach even higher speeds or reduce the number of fibers required at a given speed. For instance, a 100G channel would require four 25G duplex fiber pairs instead of ten 10G duplex fiber pairs.


In network applications, serial transmission is often used in 10G connectivity, while for 40G and 100G connectivity, parallel transmission is preferred. Hope you could acquire some useful information from the article, and have a better understanding of these two data transmission methods. In addition, you can find fiber optic cables mentioned above in FS.COM. Some other fiber optics are also available here, such as 24-fiber MPO MTP loopback, MTP to LC breakout cable, MPO fiber patch panel and so on. If you want to know more details, please visit our site.

Comparison Between Base-8 Connectivity and Base-12 Connectivity

As 10G network no longer satisfies the increasing demand for high speed data transmission, many data center managers turn to 40G network. Base-2 connectivity, based on increments of two fibers, is a common type of fiber optical link in 10G network. However, this kind of connectivity is not suitable for 40G network which needs high-density cabling. For 40G network cabling, there are two popular solutions—Base-8 connectivity and Base-12 connectivity. How much do you know about these two cabling solutions? Is there any difference between them? After reading this article, you will find the answer.

Base-12 Connectivity

In Base-12 system, Base-12 connectivity makes use of fiber optical links based on increments of 12 fibers. And 12-fiber or 24-fiber MTP/MPO optical connector assemblies are usually used to accomplish the links, such as 12-fiber or 24-fiber MTP trunk cable. Here is a figure of 24-fiber trunk cable used in Base-12 system for you.

Base-12 system using a 24-fiber trunk cable

Base-8 Connectivity

The Base-8 system still uses the MTP/MPO fiber connector, but the links are built in increments of 8 fibers (as shown in the following figure). Thus 8-fiber trunk cable, 16-fiber trunk cable and 24-fiber trunk cable can be easily found in Base-8 system. Here is a figure of 24-fiber trunk cable used in Base-8 system for you.

Base-8 system using a 24-fiber trunk cable

Comparison Between Base-8 Connectivity and Base-12 Connectivity

Since the number twelve is obviously larger than the number eight, Base-12 connectivity does provide the benefit of connector with higher fiber density compared to Base-8, and thus a larger number of fibers can be installed more quickly when using Base-12 connectivity. However, as 8-fiber transceivers are utilized in most deployments of 40G network, the benefit of matching the fiber count in the MTP backbone connectivity with the fiber count of the transceiver tends to outweigh the density benefit of Base-12 connectivity. In addition, in Base-12 connectivity, four fibers for transmit and four fibers for receive, leaving four fibers unused per connection. This will lead to a significant and costly loss in fiber network utilization. But Base-8 connectivity can be a more cost-effective option for end-to-end MPO to MPO channels and architectures. In fact, Base-8 connectivity is not an universal solution and Base-12 connectivity in some cases may still be more cost-effective. The following part describes the relative benefits when comparing Base-8 versus Base-12 connectivity for a data center deployment.

Benefits of Base-8 Connectivity
  • Optimized for both 2-fiber and 8-fiber transceiver technologies.
  • Enables 100% fiber utilization for 8-fiber transceiver systems without the additional cost and insertion loss of Base-12 to Base-8 conversion devices.
  • Cable harnesses can easily route to all common port counts on switch line cards.
  • Only requires unpinned MTP patch cords for any connections within the link.
  • Most flexible solution for 40G, 100G and 400G transmission networks.
Benefits of Base-12 Connectivity
  • Higher fiber per connector density than Base-8 connectivity.
  • Compatible with the large installed base of existing Base-12 MTP deployments.
  • Where proprietary vendor specific 40G duplex 2-fiber transceiver technologies are deployed, existing Base-12 data center infrastructures offer higher fiber density per connector (Note: the vendor specific technologies are incompatible with each other, and with parallel optics,which may add a level of management complexity in a multi-vendor environment.)

Base-12 connectivity has dominated the 40G network market for years, while the Base-8 connectivity is an additional option to ensure that data centers have the most cost-effective, future-proof network available. And both of them have their own benefits. As for which one to choose, it depends on the requirements of the network deployment. I hope this article can help you have a better understanding of this two cabling solutions.