What is DDM, DOM and RGD?

If it is your first purchase of fiber optic transceivers, you may be very confused with the fuction options "DDM", "DOM" or "RGD". So, what functons do they represent? And do you need these functions? Today, we will have a detailed explanation of them.

What's DDM?

DDM, namely Digital Diagnostics Monitoring, is a technology used in SFP transceivers in order to give the end user the ability to monitor real-time parameters of the SFPs. Such parameters include optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage etc.

What's DOM?

DOM, short for Digital optical monitoring, is familiar with the DDM function. It is also a feature which allows you to monitor many parameters of the transceiver module in real-time. DOM allows you to monitor the TX (transmit) and RX (receive) of the module, as well as input/output power, temperature, and voltage. Network administrators can then check and ensure that the module is functioning correctly.

Author Note: Obviously a SFP with DDM/DOM funstion is high-ender than one which without it. This is why most of modern optical SFP transceivers support DDM/DOM functions according to the industry-standard SFF-8472.

What's RGD?

You may be confused with the difference with the SFPs with "RGD" and the one without it, or you may be interested in the "-RGD" in the product number of some SFP transceiver modules. So, what does RGD stand for? RGD means rugged transceivers. In fact, these are enhanced transceiver modules which have been designed for greater durability, and can operate under more extreme conditions. Rugged transceivers may feature enhanced ESD protection, and extended operating temperature range so that it can help eliminate field failures without the need of costly external protection devices.

Author Note: In general, a rugged SFP can be identified by its product model, ie. -RGD. Specific situations depend on the specific vendors.

Other Functions in SFP transceivers

If you have an experience of buying Cisco SFPs, you may be confused with the part number with "=", because you can not find out the difference with the one without "=" according to the specification. In fact, "=" is also called a "FRU" part where FRU stands for "Field Replaceable Units". Those are the parts that can be used as "spare" or be shipped individually to replace damaged units. But the new parts that are ordered directly from a reseller or from Cisco usually don't come with the = sign. Thus, if you want to buy an SFP transceiver with the "FRU" part, you should ask your vendor to ensure this function.

Recommended Products With These Functions

• New Cisco GLC-LX-SM-RGD compatible 1000BASE-LX/LH SFP
• New Cisco GLC-SX-MM compatible 1000BASE-SX SFP (with DDM/DOM)
• New Cisco GLC-SX-MMD compatible 1000BASE-SX SFP (with DDM/DOM)
• NEW Finisar FTLF1318P3BTL Compatible 1000BASE 1310nm 10km SFP DDM IND Transceiver Module
• NEW NETGEAR AGM731F Compatible 1000BASE-SX SFP 850nm 550m Transceiver Module (with DDM/DOM)
• NEW Juniper EX-SFP-1GE-SX Compatible 1000BASE-SX SFP 850nm 550m DDM Transceiver Module (with DDM/DOM)
• NEW Brocade E1MG-LX-OM Compatible 1000BASE-LX SFP 1310nm 10km DDM Transceiver Module

Article Source: About DDM, DOM and RGD in SFP Transceiver Module

How to Identify The Refurbished Optical Transceiver Module

Nowadays, there is a variety optical transceivers on the market and some of them may be the refurbished optical transceivers. Driven by the huge economic profit, some unscrupulous manufacturers mislead customers to use the refurbished or inferior optical transceiver modules on their switches, servers, base station equipment or storage devices. What's worse, they have even faked the famous brand optical transceiver modules. These shoddy refurbished optical transceivers illegally entered the markets may result in heavy losses to us. This article is explaining how to identify the refurbished transceiver modules, and buy a high-quality transceiver module.

Sources & Disadvantages of the Refurbished Optical Transceiver Module

Source

In general, the sources of refurbished transceiver module include the following two ways.

• Some transceiver modules have been used for certain years, and they will be eliminated due to the update of equipment or damaged due to improper use. The unscrupulous manufacturers recycle these old or damaged transceiver and refurbish them, these refurbished transceiver modules generally have serious impact on the service life.
• Some unqualified transceiver modules can not pass the on line tests and ready to destroy. These unqualified transceivers are used by the unscrupulous manufactures to fake the high-quality transceivers. However, the parameters of these transceivers are not standard. It will have a great impact on the stability of data transmission, and even have serious damages on the equipment.

Disadvantages

The generally speaking refurbished transceiver modules are referred to the secondhand or unqualified transceiver modules mentioned above. They are bought by some unscrupulous businessmen of low prices and renewed with a number of technical renovation (for example: replacing the shell, replacing the clasp, or replacing the labels, etc). These refurbished transceivers have a lower price than the original one and can easily attract the users. However, many issues have been occurred when using:

• Pollution on the light path
• Easy to damage
• Short using life
• Low receiving sensitivity
• Cannot meet the high or low temperature working environment

How to Identify The Refurbished Optical Transceiver Module

Here are three methods to identify the refurbished optical transceiver module:

• Appearance recognition. Check the appearance of the transceiver modules: new module's appearance generally has good consistency while the refurbished module is not glossy, and have some wear and scratches in the rim angle. Many refurbished transceivers are replaced with a new shell, in this case, we can see the interface of the modules, if there is dust and not smooth, it is the refurbished modules.
• Check the ferrule. Pulled out of the dust cap, we can see the ferrule in the bore. In general, the multimode transceiver has plastic ferrules or metal ferrules while the singlemode transceiver has the metal ferrule. A second-hand old module is lack of glossy, and generally rough and with scratch that has a bad consistency. The ferrules of a new quality module is brightness of color and lustre and has a good consistency.
• Put the modules working under the status of 50-60 °C and see if it is working properly. In generally, a refurbished optical transceiver module can not work well or even disconnect.

Avoiding Refurbished Transceiver Module, A Quality Vendor Is Necessary

No matter there are how many tips or methods on how to identify, the best way to avoid buying refurbished transceiver module is to choose a quality vendor. The reason why many users have bought the refurbished transceivers is the attractive low price of them. As we know, the costs for transceiver modules modules keep adding up over time. In order to save more, a low cost option of the transceiver is the expectation of the users. How and where to find a quality vendor? Fiberstore is your best choice. Fiberstore provides a full set of compatible fiber optic transceiver module solution cover all the famous brands, such as Cisco, HP, Finisar and so on, which can satisfy you with a full range of services. In addition, we can also offer the custom service for your special requirements. The following figure shows us a 10 gbps SFP 10km 1310nm transceiver module.

All our fiber transceivers are 100% compatible with major brands

Cisco, Juniper, HP, Finisar, Brocade, Extreme, Source Photonics, Netgear, Force10, Dell, Foundry, Huwei, Intel, Allied Telesis SFP and Custom SFP...

A full range of optical transceivers

SFP Transceivers (eg. 1000BASE-SX, 1000BASE-LX/LH, 1000BASE-ZX, 1000BASE-T), SFP+ transceivers (eg. 10GBASE-LR, 10GBASE-SR), QSFP+ & CFP Transceivers, XFP transceivers, 10G X2 & XENPAK and GBIC. Get more information can visit Fiberstore.com.

Recommendation of The Best-selling Brand Compatible Transceivers

• Cisco: GLC-SX-MMD, GLC-LH-SMD, GLC-T, SFP-GE-T;
• HP: 455883-B21, J9143B, JD089B;
• Netgear: AFM735, AGM731f, AGM734
• Finisar: FCLF-8521-3, FTRJ8519P1BNL, FTLF1319P1BTL

Related Articles: D-Link SFP Transceivers Alternative Solution

Learn Some about CWDM SFP Transceivers

As we know, CWDM SFP (CWDM) is on the SFP transceivers or socket switch or router port, it is a kind of technology of hybrid protocols and data rate, allow the multi-channel, combination, and through the optical fiber cable transmission.

CWDM SFP use SFP interfaces to connect devices, at the same time, double LC/PC type optical fiber connector software, optical network connection.CWDM SFP for port connected to the optical fiber network, the typical CWDM SFP as cisco can support gigabit Ethernet and fiber channel at the same time. It is compatible SFP with fast Ethernet, SONET OC – 3 and OC – 12, and STM and SDH STM – 1-4 standard.

The purpose of CWDM SFP transceivers basic characteristics are hot pluggable and double LC interface, and compliant with IEC60825-. The transmitter center wavelength ranges from 1270nm to 1610nm and the receiver PIN or APD is single +3.3V power supply, PECL data interface; Operating temperature range s from -5 to + 70 degrees;

CWDM SFP transceivers consists of three parts: an uncooled CWDM DFB laser, PIN photodiode integrates a trans resistance preamplifier (TIA) and single-chip microcomputer control unit. This optical transceiver integration in a module to send and receive channel. In the sender, serial data stream is transmitted to the the laser driver. Laser driver bias and modulation of refrigeration directly modulated laser (DML), according to the LC connector industry standard, make the data transmission of single-mode fiber. At the receiving end, the data flow from a PIN or restore the avalanche photodetector (APD), transmitted to trans resistance amplifiers, rear and then passed to the amplifier.The module has to be hot-swappable SFI standards for electrical interfaces. This integrated optical transceiver to provide signal transmission rate from 100 Mbps to 3.1 Gbps of high-speed serial link and the module in line with the small pluggable (SFP) multi-source agreement (MSA).

We know that typical CWDM SFP transceivers including CWDM-SFP-1470, CWDM-SFP-1490, CWDM-SFP-1510, CWDM-SFP-1530, CWDM-SFP-1550, CWDM-SFP-1570, CWDM-SFP-1590, CWDM-SFP-1610. Cisco CWDM SFP is a series of single-mode transceiver covers from 1470nm to 1610 nm wavelength applications, they are different colors to identify them, these CWDM SFP to gigabit Ethernet and 1/2 GBPS fiber channel applications. And another brand is Juniper CWDM SFP, it includis SFP-1GE-LH-CWDM-1270, SFP-1GE-LH-CWDM-1290, SFP-1GE-LH-CWDM-1310, SFP-1GE-LH-CWDM-1330, SFP-1GE-LH-CWDM-1350. The Cisco SFP transceiver and Juniper CWDM SFP transceivers are with excellent quality. Casting CWDM SFP transceivers work on the 80 km, with different wavelengths from 1470 nm to 1610 nm. It is fully compatible with and in its intended functions casting router or switch, and complete the MSA compatible.

Cisco’s may possibly aim at either Gigabit Ethernet or Fiber Channel. Fiberstore supply original CWDM SFP, along with other CWDM SFP transceivers, impressive company like cisco, HP, huawei, juniper networks and etc. Fiberstore, as a famous optical fiber manufacturers, provide many other kinds of fiber optic transceivers like SFP transceivers, GBIC transceiver, CWDM SFP transceivers, DWDM SFP transceivers, SGMII SFP transceivers, SFP+ transceivers, XFP transceiver, X2 transceiver, Xenpak transceiver, and so on. In addition, Fiberstore is making with 30% of the price including all SFP transceivers. So if you want to know more and take action for it immediately. The website is http://www.fiberstore.com/

Article Source: http://www.fiber-optic-transceiver-module.com/