User Guide for FS MTP/MPO Type-B Cables

Updated on Dec 15, 2021

MTP/MPO Cable Assemblies

MTP/MPO cables have multi-core connectors that provide more consistent and reliable performance when used in high-density, low-loss cabling, thus becoming an integral part of 40G/100G data transmission in large data centers. Hence, TIA standards define three types of polarized MTP cables: Type A, Type B, and Type C. Different types of MTP polarity cables may have different applications. In this tutorial, we will mainly introduce type-B polarity MTP cables and their applications. For a complete polarity guide of FS MTP cables, you can refer to the white paper Understanding Fiber Polarity.

Table of Contents

MTP/MPO Type-B Cable Overview

MTP/MPO Type-B Cable Categories

MTP/MPO Type-B Cable Applications

MTP/MPO Type-B Cable Overview

The type-B polarity MTP cable meaning is to use a key-up connector on both ends of the cable. Often referred to as a 40G MTP cable, the type-B MTP cable is extremely versatile. This cable assembly can be used to plug directly between your 40G QSFP+ optic transceivers. As you can see in the diagram, this cable has a "flipped" polarity and will result in a Pin 1 to Pin 12 relationship. This is extremely useful because 40G optics utilize parallel optics, meaning instead of alternating Tx and Rx in a duplex pattern, the port will look like the following diagram.

mtp type-b cable Figure 1: Type-B polarity MTP cable

MTP/MPO Type-B Cable Categories

Based on its different functions, MTP type-B cable can be divided into two main categories: MTP Trunk cables and MTP-LC breakout cables. Depending on the nature of the socket MTP trunk cables are further divided into female-female, female-male, and male-male. When connecting two 40G SR4 QSFP+ transceivers in parallel optics, only female-female type B MTP cables should be used. For MTP-LC breakout cables, female MTP-LC breakout cables and male MTP-LC breakout cables are available.

Note: MTP connectors can be divided into female connector and male connector. Female connector does not have guide pins, while male connector has two guide pins. The connections between the connectors are precisely aligned with the pin, and the two MTP connectors connected to each other must be male and female.

Category Fiber Mode Gender Fiber Count Polish Type 40G Ethernet Distance 100G Ethernet Distance Wavelength
Type-B MTP/MPO Trunk Cables OS2,OM4,OM5 Female-Female,Male-Male 12-Fibers,8-Fibers UPC to UPC 150m at 850nm,440m at 850nm 150m at 850nm 850/1300nm,1310/1550nm
Type-B MTP/MPO-LC Cables OM4,OS2 SMF Female-4 LC,16 APC(Female)-8 LC UPC 8-Fibers LC UPC 150m at 850nm 400m at 850nm 850/1300nm,1310/1550nm

mtp type-b cable Figure 2: Type-B polarity MTP cable types

MTP/MPO Type-B Cable Applications

Due to the special construction of MTP type-B cable, a female connector MTP cable is usually needed to match the male connector MTP cable. The male guide pin fits into the female bore to ensure precise fiber alignment. Attempting to mate two female or male connectors can result in light loss or damage to the fiber splice. The following examples focus on the application of female MTP type-B cables.

40G-40G Direct Connection: Female to Female MTP/MPO Type-B Polarity Trunk Cable

Except for the parallel 40G optical transmission mentioned above, female to female type-B trunk cable also can be used for direct switch to switch connectivity with no patch panels. The following figure shows two Cisco 40G switches connected by a 12-fiber MTP female cable directly.

mtp type-b trunk cable Figure 3: Female to female 12-fiber type-B MTP cable in 40G connection

Products Gender Max Data Rate Cable Type Connector 40/100G Ethernet Distance Fiber Mode
Cisco QSFP-40G-SR4 Compatible QSFP+ 850nm 150m DOM Transceiver Module / 42Gbps (4×10.5Gbps) MMF MTP/MPO-12 Male / /
MTP/MPO Type-B Cable Female to Female / / US Conec MTP® Female 150m at 850nm OM4 50/125μm

With an MTP adapter, a type-B MTP polarity trunk cable can be used for connecting a patch panel and a QSFP+ SR4 transceiver.

40G-4x10G Direct Connection: Female MTP to LC Type-B Polarity MTP Breakout Cables

How to connect a 40G switch to a 10G switch? A female MTP-4xLC type-B breakout cable can solve this problem easily. The following figure shows the four 10GBASE-SR transceivers interconnect with one 40GBASE-SR4 transceiver by one female MTP-4xLC breakout cable directly.

type-b mtp-lc harness cable Figure 4: 8-fiber type-B MTP-LC breakout cable in 40G connection

Products Wavelength Max Data Rate Cable Type Connector Fiber Mode
Cisco QSFP-40GMTP/MPO MMF Optical Transceiver 850nm 42Gbps (4×10.5Gbps) MMF MTP/MPO-12 Male /
Cisco SFP-10G-SR SFP+MMF Transceiver 850nm 10.3125Gbps VCSEL LC Duplex /
Female to 4 LC UPC Duplex 8 Fibers Type B Plenum Breakout Cable 1310/1550nm / / LC UPC Duplex OS2 SMF 9/125μm

40G-40G Interconnections: Type-B MTP/MPO Trunk Cables and Type-B MTP Breakout Cables

Type-B MTP trunk cable and breakout cable can be used together to achieve high performance fiber networking. Figure 5 shows the interconnect of 10GBASE-LR SFP+ transceivers connected by type-B MTP trunk cable and breakout cable. It is an ideal solution for connecting two 40G Cisco switches in a data center by completing the direct connection of MTP fibers through fiber optic panels, simplifying cabling, and performing high-speed fiber optic transmission.

mtp type-b trunk cable and harness cableFigure 5: type-B MTP trunk cable and breakout cable in 10G interconnection

Products Wavelength Max Data Rate Cable Type Connector Fiber Mode
Female to 4xLC UPC Duplex 8 Fibers Type B Plenum Breakout Cable 1310/1550nm / / LC UPC Duplex OS2 SMF 9/125μm
Male to Male OM4 Multimode Elite Trunk Cable 850/1300nm / / US Conec MTP® PRO Male OM4 50/125μm


MTP/MPO Type-B cable completes high-speed data transmission with its unique multi-core interface. You can choose the right cable interface according to your network equipment needs. FS.com offers base-8 and base-12 MTP/MPO Type-B as 10/40G direct and interconnect, improving fiber utilization, simplifying cabling, and enabling data centers to efficiently migrate to 40/100G or higher speeds.

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