NEMA & IEC Power Cord Types, Differences & Buying Guide

NEMA and IEC power cords are devices that have been used a million times in our lives. but most people don’t know what an IEC or NEMA plug is. NEMA, namely National Electrical Manufacturing Association, is the industry group that sets standards for use in electrical products. And IEC(International Electro technical Commission) is a non-profit & non-govt organization that publishes international standards for AC interconnections between equipment. There are several different types of connectors and interfaces that are used all over the world. This article describes the concepts, types and designation of NEMA & IEC power cords, as well as buying guide.

Where Thers’s Power, There’s a Power Cord

Power cord is a line cable or main cable that contains a pair of connecting couplers on either of its ends. Both ends are detachable from the electrical supply and device. It bears the burden of temporarily connecting a portable electronic appliance with the main electrical supply line and can easily and readily pass through a wall socket or an extension cord.

power cords

Just as the above image shows, the power cord assembly consists of two major parts. One is the cable plug. It is a male connector. Its use is for connecting the AC outlet to provide electricity. The other is the receptacle on the other end. Receptacle part acts as the female connector, which attaches to the equipment. There are several different types of connectors and interfaces used all over the world. The NEMA and IEC power cords described here are the commonly used in North America.

NEMA Power Cord—A North America Standard

The establishment of National Electrical Manufacturing Association (NEMA) certificates various power cord types throughout North American and other countries, ranging in amperages from 15-60, and in voltages from 125-600. Unique, non-interchangeable different plug types are created based on specific amperages or voltages.

There are many variants of the NEMA plugs available in the united states and north America countries, but NEMA 1-15-P & NEMA 5-15-P are the most common among them. NEMA type 1 consists of a round pin or prong right below the two flat prongs, while NEMA type 5 uses a third pin for grounding purposes.

NEMA 1-15-P—Two-Pole, No Ground

The NEMA 1-15-P is normally referenced as a two-wire non-grounding device that fits into a standard 110 VAC wall outlet. Rated for 125 V maximum, NEMA 1-15-P has two flat blades, just like the NEMA 5-15 plug, but has no ground pin. The female mating outlet for the 1-15-P is called a 1-15-R (R for “receptacle”). Most current versions of this plug have one blade slightly wider than the other.

NEMA 1-15-P power cord

Ungrounded NEMA 1 plugs are still popularly used by manufacturers of small appliances and electronic devices because of the design’s low cost and compact size, and they are upward compatible with modern grounded NEMA 5 receptacles.

NEMA 5-15-P—Two-Pole with Ground Pin

The NEMA 5-15-P is a 3-prong grounded device which plugs into a standard 110 VAC wall outlet. The connector has two flat parallel blades, with a round ground pin located between and above them. The female mating outlet for the 5-15-P is called a 5-15-R (R for “receptacle”).

NEMA 5-15-P power cord

IEC Power Cord—An International Standard

IEC power cord, either IEC 60320 or IEC 60309, is available in different combination of earthing, for temperatures and specific needs. When using these connecting couplers, the merchants just need to change the power cord that comply with these standards to achieve worldwide compatibility.

IEC 60320 Power Cord

IEC 60320 is recognized as the international standards used by most countries in the world, which specifies non-locking appliance and interconnection couplers for connecting power supply cords to electrical appliances up to 250 volts. The “320” refers to the number of the specification that describes power connectors. Different IEC 60320 power cord types ranging from C1 to C24 are specified for different combinations of current, voltage and temperature. For detailed information, please visit: How Much Do You Know about Power Cord Types?

IEC-C13-C15-C19-connectorNote: C13, C15, C19 are the most commonly used ones in data centers.

IEC 60320 C13 Vs. C15 Power Cord

Form the above image, we can easily see that IEC C15 is similar to the C13 power cord except for a notch opposite the earth in the C15 connector. In addition, IEC-C15 connectors will work in the C14 inlets however, IEC C13 connectors won’t fit into C16 inlets.

The IEC C15 connectors are specifically designed for higher temperature devices (up to 120°C), for example electric kettles, computing networking closets or server rooms, and PoE (Power over Ethernet) switches with higher wattage power supplies. While the standard IEC C13 power cord that runs everything from desktop/personal computers, monitors, printers and amplifiers to fixed-configuration switches. They are typically rated at 15A/250V (domestically) and 10A/250V (Internationally) with the temperature rating at 70°C.

Buying Guide

It is extremely important to choose the appropriate power cord that will deliver high performance in terms of speed and durability. Following a few simple steps will help you make the right choice.

  • Identify the Correct Plug for the Country of Export

When deciding on the correct plug pattern, keep in mind that while some look similar that does not mean it is the right cord for the equipment. For example, removing a NEMA power cord from a cord set made with North American cable and replacing it with a Continental European plug (CEE 7/7 power cord) will not make the cord set acceptable for Europe.

  • Confirm the Voltage

The voltage rating for plugs in north America ranges from 100-127 to 200-240. Higher or lower amperage can mean a different plug pattern, even in the same country. It will destroy appliances if the 125 volts power cord is mistakenly inserted into a 220 volts receptacle,

  • Check the Current Rating of the Power Cord

Another specification to check is the current rating, the rating for north America are different from other countries 15, 20 and 30.

  • Choose the Plug Type, if Utilizing a Cord Set

The number of prongs in a plug varies from 2 to 5. The prongs can be oval, round, straight blade, and rectangular in shape. For North America, there are NEMA 5-15P and NEMA 5-20P. Knowledge of the current rating and voltage can help discern between the four types and choose the correct plug.

Final Words

When using power cord, it is essential to protect yourself and your tools with a proper ground system. FS.COM AC power cords e.g. IEC power cords, Locking power cords, NEMA power cords, etc. are available in optimal lengths and various colors. Power cord with one end of NEMA connector and the other end with IEC320 plug, are designed to meet multiple application environment.

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Switch Cascading: With SFP Port or Standard RJ45?

Gigabit switch that offering greater speeds and compatibility has gained in much momentum in the field of networking. And with the unceasing demand for more bandwidth, network will grow to the point that we need to connect several gigabit switches together. Switch cascading is one of the options to link more than one gigabit switches. But here comes the problem: should I cascade switches via a SFP port (copper SFP module or fiber SFP module) or just through standard RJ45 ports? Is there any difference in regard to the speed and distance. This is we’re gonna explore in the article.

What Is Switch Cascading?

Cascading more than one switches enables us to have multiple ports interconnecting each of the switches in the group. But they are configured and managed independently. Switches that are cascaded together should all support Spanning Tree Protocol (STP), in order to allow redundancy and to prevent loop. Generally switches of any models or from any manufacturers can be cascaded. There are two options to cascade switches, either use copper SFP (1000BASE-T SFP) and fiber SFP port or via standard RJ45 port on the Gigabit switch.

SFP Port on Gigabit Switch

SFP port enables Gigabit switches to connect to a wide variety of fiber and Ethernet cables in order to extend switching functionality throughout the network. The SFP port allows the switch to connect to fiber cables of different types and speeds via fiber SFP module, or even connect to Ethernet copper cables through copper SFP module. As hot-pluggable I/O devices, both fiber SFP and copper SFP models can be used on a wide variety of products and intermixed in combinations of 1000BASE-T, 1000BASE-SX, 1000BASE-LX/LH, 1000BASE-EX, 1000BASE-ZX, or 1000BASE-BX10-D / U on a port-by-port basis.

SFP Module Type
Cable Type
Transmission Distance
Maximum transfer rate (distance of 1000m)
Copper SFP Module
Cat5 network cable
1000 Mbps/1 Gbps
Fiber SFP Module
Duplex LC
Fiber patch cable
≥ 100m
1000 Mbps/1 Gbps

RJ45 Port on Gigabit Switch

RJ45 ports are built-in ports in Gigabit Ethernet switch. To connect two RJ45 ports, Cat5e or Cat6 copper network cables are generally adopted. Here lists the specification of each network cable.

Max Transmission Speed (at 100 m)
Max Bandwidth
Cat 5e
1000 Mbps / 1 Gbps
100 MHz
Cat 6
1000 Mbps / 1 Gbps
100 MHz

Cascading Switches: SFP Port vs. RJ45 Port

So, here we have literally three options to cascading two switches:

  • Connect SFP port of the two switches via fiber SFP module and fiber patch cable
  • Connect SFP port of the two switches via copper SFP module and copper network cable (Cat 5e/Cat 6)
  • Connect the built-in RJ45 ports via Cat 5e or Cat 6 network cable

sfp port fiber sfp copper sfp

For fiber SFP port vs. copper SFP (or bulit-in RJ45 ports ), the benefit of using the fiber SFP port for switch cascading is that you will have more Ethernet ports available for your end points connections. Besides, both RJ45 ports and copper SFP module use electric signal to transmit data, fiber SFP module, however, uses light signal can tolerate longer distances and is less prone to interference. The other criteria is that fiber SFP module in most Cisco SFP switches is capable of higher speeds than the normal copper ports.

While for copper SFP vs. RJ45 ports, things become far easier. As they both utilize electric signal to transfer, the two options are basically the same. Except that the copper SFP module would generate extra costs and increase installation time. So when it makes sense to use copper SFP module instead of RJ45 ports? Only for cases where you need to connect between an all-SFP distribution switch and an all-copper edge switch. The reason the switches have SFP slots is to support connecting to a fiber optic network, either to talk to other fiber optic gear or especially to connect over distances that copper transmission can’t support at gigabit speeds.


It is thus clear that the choice between fiber SFP vs. copper SFP vs. Rj45 port when cascading switches actually depends on your specific cabling environment, and where the cable run is going. FS.COM offers a broad range of copper and fiber optic transceivers that fully compatible with major vendors on the market, which makes us the vendor of choice for optical network components and solutions. For any further information, please visit or contact us directly via

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Mini GBIC vs SFP: Is It the Same?

We’ve got very familiar with GBIC transceiver: short for gigabit interface converter, it is developed in 2000 as a hot swappable transceiver that commonly used in Gigabit Ethernet and Fiber Channel. But as the demand for higher bandwidth and transmission speed keeps accelerating, more ports are needed to be fit in a line card. So Mini GBIC module is developed to provide more interface in the same line card. Mini GBIC is a smaller version that only half the size of GBIC transceiver. So what exactly is Mini GBIC module? Mini GBIC vs SFP: Is It the same? This article will handle all the confusions for you.

What Is Mini GBIC Transceiver?

Mini GBIC, also called SFP transceiver (SFP means small form factor) was announced in 2001, it has the same functionality with former GBIC module but built with a smaller form factor. Mini GBIC and SFP transceiver actually refers to the same thing, and they are interchangable. Mini GBIC transceiver is a compact, hot-pluggable module that can be installed and removed while the switch is powered on. Mini GBIC provides flexibility for utilizing fiber Gigabit connections in both data and telecommunication applications. So the shipment of Mini GBIC had soon outgrown GBIC transceiver and secured its position in Gigabit SFP based network.

mini gbic vs sfp transceiver

What Is a Mini GBIC Used For?

Mini GBIC transceivers allow technicians to easily configure and upgrade electro-optical communications networks. It is a plug-in module that can be removed and replaced without turning off the system. Mini GBIC transceiver is typically employed in fiber optic and Ethernet systems for high-speed networking. The data transfer rate is one gigabit per second (1 Gbps) or more. Mini GBIC are designed for high performance integrated duplex data transmission over optical fiber. designed to support SONET, Gigabit Ethernet, Fiber Channel, and other communications standards.

Mini GBIC Transceiver Classification

Mini GBIC can be classified into different groups according to data rate, operating wavelength, transmission distance and etc.

Divided by rate :155M/622M/1.25G/2.125G/4.25G/8G/10G,155M and 1.25G market is more used.

Divided by wavelength : 850nm/1310nm/1550nm/1490nm/1530nm/1610nm.

  • The 850nm wavelength is SFP multimode, and the transmission distance is up to 550 m.
  • 1310/1550nm is SFP single-mode, and the transmission distance ranges from 2 km to 80 km.

The bare Mini GBIC module basically has no difference if they have no mark, so the manufacturers make different colors of pull ring to distinguish them.

  • Black pull ring is multi-mode, the wavelength is 850nm;
  • Blue is the 1310nm module;
  • Yellow is the 1550nm module;
  • Purple is the 1490nm module and so on.

Divided by distance: Mini GBIC transceiver can also be classified by different transmission distance, see the following table:

mini gbic or sfp module types


Mini GBIC transceiver, with its small and low-cost advantages to meet the needs of high-density transmission, has replaced GBIC transceiver to become mainstream in data center. FS.COM offers a broad range of Mini GBIC transceiver that fully compatible with major brands on the market. Each of our optical transceivers is tested on the brand switch in strict environment to ensure performance and reliability. For more details, please visit or contact

Related Article: GBIC vs SFP: When It’s Best to Use GBIC and When to Use SFP
Related Article: SFP Module: What’s It and How to Choose It?

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Can GPON SFP Be Plugged Into My Own Switch?

Fiber has been introduced to average homes and businesses for a spell and it has different names from different service providers: Google Fiber, Verizon FiOS, AT&T GigaPower, UFiber, etc. GPON is one of the key technologies that are used to deploy these fiber-based access networks (FTTx). Though it is called GPON from its emergency to its prosperity, some details in utilizing GPON services have changed. Early GPON adopters may still remember the doubled devices the provider installed in their houses. But now things seem to be easier in adopting GPON for both the service provider and the end user. Optical Network Termination (ONT) or Optical Network Unit (ONU) GPON SFP module is the new kid in GPON applications and customers are not familiar with them enough.

GPON SFP module

ONT/ONU: From Optical Modem to GPON SFP Module

What is your ONT like? Previous ONT is an optical modem. It usually has an SC/APC port for connecting the SC fiber cable, some fast Ethernet or gigabit Ethernet (LAN) ports. Some has a phone port for VoIP service. Apart from a modem, the service provider also lends an IP access router to the customer. If there’s television service required, a Set-Top-Box or a video recorder is also needed. Some Internet service providers (ISPs) put an integrated ADSL router (modem + router).

optical modem with an SC port

ONT/ONU GPON SFP module is a bidirectional single-mode SFP module with a simplex SC receptacle. The adoption of GPON ONT SFP is considered a significant improvement in GPON optical networks. Compared with its predecessor, the SFP format has much smaller size than traditional ONTs/ONUs. Besides, it cut down the equipment that need to be provided by the ISP, which also make it easier for customers to connect their diverse data, voice and video devices.

Can I Use GPON SFP Module in My Own Switch?

Since the GPON ONT has been condensed with a small form-factor pluggable (SFP) packaging, can it be plugged into the end users’ switch/router as other SFP modules do? In most scenarios, the answer is yes. Several reasons can prove how it is possible.

Firstly, the GPON ONT module is in standard SFP format. Such a packaging allows the GPON ONT module to be plugged into any standard MSA-compliant SFP port. This is the basis for its use in other devices not provided by the ISP.

Secondly, it has been stated by the vendors of GPON ONT SFP modules that their ONT SFP can be used in a wide range of wired and wireless products with SFP port, such as Huawei MA5671A ONT SFP. The datasheet of this GPON ONT SFP says it can be plugged into the SFP port of any customer- or carrier-owned terminals, including switch and router. Also it can be used in WiFi access point (AP) with SFP slot and to transmit wireless traffic over GPON.

Thirdly and most importantly, there are home users or engineers who have tested PON ONT SFP modules in different networking devices. During the installation of GPON services, some users required to use their own routers instead of the router provided by the ISP. It was approved by the ISP and they whitelisted the users’ router so that it can interoperate with the OLT in the Central Office. What the users needed to do was just to plug the GPON ONT SFP in the SFP port of the router and then plug the SC fiber patch cord into the receptacle of the GPON ONT SFP. The only hard point in this process is to get the support from your ISP. (If you are interested, these using cases can be easily found on google.) In addition, the test of GPON ONT SFP modules from different vendors has been down as well. Most manufacturers’ GPON SFPs can be used in any switches/routers/gateways with SFP ports. But this is the ideal case, not given that some picky original switches/routers may refuse to or the GPON ONT SFP is not a quality one.


GPON SFP is a small transceiver module that allows effective and low-consumption transmission over GPON. And the use of GPON ONT/ONU SFP module at the customer side is even more convenient than previous installations. Theoretically and practically, a standard GPON ONT SFP can be used in any switches/routers/gateways/APs with standard SFP ports. The only question is to get the approval of your ISPs.

Related Article: ABC of GPON SFP: Understanding GPON OLT / ONU / ONT SFP Module

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How to Build a Data Center of 40G Networking With 32-Port 40G Switch?

Earlier before this year we did not anticipate the shared bikes would be widely spread all over the world, but now at the end of this year they are already everywhere. Shared bike is one of the instances of the Internet of Things (IoT), and there are many other applications that have witnessed the development of network-dependent technologies, such as self-driving cars, smart mobile phones/pads, etc. They are all calling for high bandwidth and low latency. But the old network infrastructure of data centers is not capable enough in such an environment, especially for those data centers that should deal with a huge amount of traffic. So some data centers are upgrading from 10G networking to 40G networking by using 40 Gigabit Ethernet switch, of which a 32-port 40G switch is a typical choice.

Limits of Old Data Center Network Infrastructure

What are the limits of old data center network infrastructure? In the past, the major traffic in data centers is in the north-south direction. As for data center switches, it is enough to use 10G uplink ports between the Top of Rack (ToR) switches and the aggregation switches. But as new applications and services rapidly emerge, the traffic between the end user and the data center is increasing, and the traffic in the east-west direction within the data center is increasing as well. Issues of congestion, poor scalability and latency occur when data centers keep using traditional network infrastructure.

The New Fabric for Data Center 40G Networking With 32-Port 40G Switch

In order to meet the requirements of the ever increasing network applications and services, data centers are constantly seeking better solutions. The primary problems are about bandwidth and latency. So one important thing is to upgrade from 10G networking to 40G networking. Since the 40G switch price and the 40G accessory price have dropped a lot, it is feasible to deploy 32-port 40G switches in the aggregation layer. In order to reduce the latency, it is wise to adopt the new spine-leaf topology compared with the old topology.

Scaling Example by Using 32-Port 40G Switch

A network based on the spine-leaf topology is considered highly scalable and redundant. Because in a spine-leaf topology, each hypervisor in the rack connects every leaf switch. And each leaf switch is connected to every spine switch, which provides a large amount of bandwidth and a high level of redundancy. In a 40G networking, it means every connection between the hypervisor and the leaf switch, the leaf switch and the spine switch is both at 40G data rate. In a spine-leaf topology, the leaf switches are the ToR switches and the spine switches are the aggregation switches.

data center 40G networking in spine-leaf topology

One principle in spine-leaf topology is that, the number of leaf switches is determined by the number of ports in the spine switch, at the same time the number of the spine switches equals the number of connections used for uplink. For a 32-port 40G switch like FS.COM N8000-32Q, it can have a maximum of 32 40G ports, but some ports should be used for uplinks to the core switches. In this case, we use 24 40G ports for connectivity to the leaf switches, meaning there are 24 leaf switches in each pod. The leaf switch we use is the FS.COM S5850-48S6Q, a 48-port 10Gb switch with 6 40G uplink ports. Each leaf switch has 4 40G uplinks to the spine switch. Then each spine switch connects to the two core switches.

data center 40G networking with 32-port 40G switch

Better Enhance the 40G Networking by Zones

This new data center fabric by using 32-port 40G switch is an improvement in bandwidth and latency, but it is not perfect either. For every network switch, it has limits on its memory, including the memory of MAC addresses, ARP entries, routing information, etc. Particularly for the core switch, the number of ARPs it can store is still limited compared with the large number it has to deal with.

Therefore, there’s need to split the network into zones. Each zone has its own core switches, and each pod has its own spine switches. Different zones are connected by edge routers. By adopting this design, we are able to expand our network horizontally as long as there are available ports on the edge routers.

data center 40G networking with 32-port 40G switch optimized by zones


The transformation of data centers is mainly due to the demand of the users. The increasing amount of networking applications and traffic pushes data centers to evolve from old fabric to new fabric. So some data centers have changed from 10G networking to 40G networking by using 40 Gigabit Ethernet switch as spine switch like 32-port 40G switch. And better optimized design is adopted to ensure the desired performance of the new 40G network.

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