The internal structure of the DAC twinax cable (Direct Attach Copper cable) is a twisted pair copper cable, and the module SFP/QSFP is connected at both ends, which can be directly electrically connected to the active device when used. The modules at both ends cannot be removed from the cable, so all DAC cables have a fixed length. Compared to using a combination of fiber optic cables and optical transceivers, the transmission distance of DAC cables is shorter and cannot be changed. But the transmission distance of a high-speed DAC cable can be selected from 0.5M to 15M. Attach SFP/QSFP DAC cables to connect one port/line card to another SFP/QSFP. A QSFP/QSFP28 breakout DAC cable will allow one port to connect to up to 4 SFP other ports.
What is DAC Twinax Cable?
Direct attach copper cable, or DAC cable, is a high-speed copper cable assembly composed of shielded Twinax copper cable with pluggable connectors on either end. The size of the cable, or gauge, is measured in American Wire Gauge (AWG) and can range from 24 to 30 AWG. The cable length will dictate the required AWG rating – the longer the distance, the higher the AWG rating should be. DAC cables are commonly used to connect switches to routers or servers for short transmission distances. In addition, DAC cables are available in several different categories: SFP+ DAC, XFP DAC, QSFP DAC and more. Every category delivers diverse benefits relying on the application. For example, SFP+ DAC cables are typically used for data centers and computer networks that require high data rates and low power consumption. Whatever the application, DAC cables provide a reliable and efficient connection.
Application of DAC Cables
DAC cables are used in various applications in data centers and can be used directly without changing existing cabling structures. Generally, this direct connect copper cable is suitable for the following applications: ToR (Top of rack) and adjacent racks – Both passive and active DAC cables are suitable for shorter ToR or adjacent racks. Middle of Row – As long as the distance is not more than 15m, an active DAC cable may be the best solution for this application. End of Row – DAC cables are ideal for end-of-row architectures as long as the distance is right. Typically, higher data rate DAC cables such as 100G/40G are backward compatible with a lower data rate of 25G/10G DACs. DAC is cheaper for data centers than optical modules and fiber patch cords.
Advantages of DAC Twinax Cables
The DAC cables are becoming popular in data center applications for their many advantages over conventional optical fiber cables. One advantage is that DAC twinax cable consume less power than optical transceiver modules. This is because DAC cables do not need patch panels or additional cables when connected to devices. Another advantage of DAC twinax cable is their simplicity of deployment. No need to worry about maintenance problems and loss caused by plugging and unplugging the DAC cable when using it. It can be directly connected to the ports on both ends.
Moreover, the heat generation of the Direct Attach Copper cable is much lower than that of the optical module due to its lower power consumption. This can make deploying DAC cables much simpler and more convenient for installers. DAC cables are also less costly than optical fiber cables, making them a more attractive option for many applications.
Source@techsaa: Read more at: Technology Week Blog