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What are the advantages and disadvantages between 40G DAC high-speed cables and QSFP+ optical modules?
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40G QSFP+ DAC high-speed cable and QSFP+ optical modules can be used as 40G network transmission solutions, 40G QSFP+ DAC high-speed cable applications are more in the data center of the short-distance transmission, low-cost, convenient cabling and other advantages, and 40G optical modules can be realized in the long and short-distance transmission, each with its own merits! The actual application needs to be adopted according to the cabling program.

40G QSFP+ DAC High Speed Cable

40G high-speed cable (DAC) refers to both ends are equipped with fiber optic transceiver connection cable, can achieve 40Gbps data transmission, is a very cost-effective high-speed interconnect solution. 40G high-speed cable can be divided into 40G QSFP + to QSFP + DAC, 40G QSFP + to 4 * SFP + DAC, 40G QSFP + to 4XFP + DAC three types, the first two types are more practical applications of the first two types. DAC three types, in the actual application of more is the first two types.


40G QSFP+ to QSFP+ DAC is composed of two 40G QSFP+ fiber optic transceivers and copper core cable, which can be used to achieve the interconnection of existing 40G QSFP+ ports to 40G QSFP+ ports by using this kind of high-speed cable, which can only be done for distances up to 7m in general.

40G QSFP+ to 4×SFP+ DAC is composed of one 40G QSFP+ fiber optic transceiver, copper core cable and four 10G SFP+ fiber optic transceivers, mainly used to realize the interconnection between 40G and 10G devices (NIC/HBA/CNA, switch devices and servers), generally can only be done for distances up to 7m.

40G QSFP+ to 4XFP DAC is composed of one 40G QSFP+ fiber optic transceiver, copper core cable, and four 10G XFP fiber optic transceivers. Because XFP fiber transceiver does not have DAC copper cable standard, the equipment to the signal compensation is low, the cable itself is very high loss, can only do short-distance transmission, generally can only do the distance of 2m or less, so this high-speed cable can be used to achieve the existing 40G QSFP+ ports to the interconnection of the four XFP ports.

40G QSFP+ Optical Module

40G QSFP+ optical modules are four-channel, small, pluggable optical modules with a transmission rate of 40Gbps, which can interconnect network devices (such as switches, routers, media converters, and other similar devices) with fiber-optic cables or copper cables, and have a more compact structure than CFP optical modules, making them more suitable for applications with high port density. 40G QSFP+ optical modules are more commonly classified as 40GBASE-SR4 optical modules, 40GBASE-LR4 optical modules, 40GBASE-ER4 optical modules, and 40G LR4 PSM optical modules.


The interface of 40G SFP+ SR4 optical module is MPO/MTP with 4 independent full-duplex channels, which is often used with multimode fiber, and the transmission distance is 100m when it is used with OM3 fiber optic patch cord, and 150m when it is used with OM4 fiber optic patch cord.

The interface of 40G QSFP+ LR4 optical module is LC duplex, which has the advantages of high density, high speed rate, high capacity, low cost and low power consumption, and is usually used together with LC single-mode fiber patch cable, and the transmission distance is up to 10km.

The interface of 40G LR4 PSM optical module is MPO/MTP, which adopts Parallel Single Mode (Parallel Single Mode Technology,PSM), utilizing 4-channel parallel design of MPO/MTP interface, the transmission distance is 10km, featuring high port density and low cost.

40G QSFP+ ER4 Optical Module is used with LC single-mode fiber as 40G QSFP+ LR4 Optical Module, the difference is that 40G QSFP+ ER4 Optical Module converts four input channels of 10G data into four channels of CWDM optical signals, each with a rate of up to 11.2Gbps, and multiplexes them into a single channel for 40G optical transmission. The main applications are 40GBASE-ER4 Ethernet links, InfinibandQDR and DDR interconnects, and client-side 40G telecom connectivity.

Walsun can provide you with 40G QSFP+ DAC high-speed cables, 40G AOC active fiber optic cables, QSFP+ optical modules and MPO fiber optic patch cords and other transmission equipments for 40G network cabling solutions.

Most high-density data center fiber optic cabling systems nowadays use: plug and play, high-density, scalable, pre-terminated fiber optic cabling system solutions.