About the dangers of second-hand old fiber module analysis

Currently on the market a lot of manufacturers for profiteer at a low price by dumping optical fiber communication equipments and widespreading the use of second-hand old fiber module production of fiber optic network equipments, such as optical switches, optical transceiver, optical transceiver, etc. This kind of unfair speculation to the fiber optic network market brings great harm and hidden trouble. Here is one of the "secret" and the analysis of the masses of users:
A source, second-hand old optical fiber module.
Second-hand old main sources of optical fiber module has two kinds: one kind is dismantle electronic waste which has been used for a certain fixed number of years because of equipment update or damage. For example, Britain's environment department has recently said that in the UK each year 12 million tons of garbage were shipped to China, India, Indonesia and other countries. The rubbish includs old TV, computer, tires, and even life rubbish. Other electronic waste shipped from Japan, the United States and other countries to developing countries as China is endless. The other kind is unqualified products from the production lines of some light module manufacturers at home and abroad. This part of electronic wastes are shipped by some unscrupulous businessmen in the form of weighing on the edge of a large number of repurchase and renovation, and then into the communications market in great quantities to seek profits. At present in the communication market, situation in the use of second-hand old fiber module optical transceiver is the most serious. The used optical fiber, used optical module, and used a refurbished chip transceiver are characterized by its low price. Lots of them flood into the market and the problem is getting more and more serious. Using second-hand light optical transceiver module is like installing a time-bomb and it could lead to network collapse at any time.
Secondly, the second-hand light performance analysis module
1, Light pollution. Both inside and outside  of the light path in the cavity with dust can affect the light path. It will affect the optical signal transmission quality and light power will be reduced, such as receiving sensitivity reduction or too much attenuation. To complete the transfer process is bound to make them overwork as the working current of the other components will be too large. Normal module working current is normally 130 ma, while the working current of the old module can reach about nearly 200 ma. This kind of module in the condition of working will be very hot. The high temperature not only affects its working performance and life of itself, at the same time can also affect the performance and life of the surrounding components. Under normal circumstances, using second-hand optical modules and devices of optical transceiver decreased to one over ten, for the normal life it will be even lower. If the laser is causing too much electricity, the result will be more dangerous. Normal threshold current general is around 10 ma, and the laser threshold current can reach 20-30 ma. Current congress makes the life of the laser attenuation sharply form a vicious circle.
2, Receiving a low sensitivity. A large second-hand old module receiving sensitivity can not meet the ITUT. G. 957 and IEEE802.3 u international standards. Although sometimes ordinary tests will not lose package, but in a bad environment or intense work conditions a little farther distance will lead to packet loss as influence on the network quality.
3, Damage on second-hand old fiber modules outside the cavity. External cavity body material for light module is normally made with plastic or metal materials, and this connector plug will cause a certain degree of wear and tear on the external cavity wall. In this way the light transmission device cannot assure alignment so that the optical device of a certain changes in the optical path as small light power, big error rate, abnormal extinction ratio. The reflects on the device will  be packet loss rate increas, the network delay, unstable system, even more seriously the network will not get through for a long time. 
4, Service life. The service life of the new optical fiber module is generally in more than five years. As the second-hand old fiber modules have been used for many years, the inside of the laser and related device are close to failure and they may fail compeletely at any time.
5, Using temperature. Generally the light of the light source module can endure the temperature of 0-70 degrees, but the old fiber module is hard to meet the requirements.
Thirdly, there are some identification methods of second-hand old optical modules.
1, Appearance recognition. The look of the new module is better, while the  shell of old module products is often old after a long time of use. Some of them may even have some wear, scratches and ash.
2, Through dustproof sleeve, sleeve can be seen. Multimode generally has two kinds of plastic and metal casing pipe; second-hand old casing degree of optical fiber is poor, coarse, and the intuitive feeling is bad. Single mode is usually metal casing; second-hand old casing has the lining of the draw good and the metallic is poorer. For a new module of casing colour and lustre is often light, smooth, good consistency.
3, The module in the environment of 50 to 60 degrees test is working correctly.
4, Market comparison. Currently, a large number of used products flood into the market with a link brand with low price. However, in fact, the brand is a primary state. It does not belong to any of the company's registered trademark. As a result, many small workshops with one or two people in charge of the assembly dump a large number of those used products in the market at very low price. Because of the brand's poor situation, all kinds of inconveniences are caused for many customers after purchase.