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HTD dedicates to provide high quality products to our clients. Our connector testing items include but not limited to insertion loss, return loss, ferrule enface, 3D interference test and tensile value.

HTD strictly follows clients’ requirement in product manufacture. If clients have requirement in measuring parameters, we will double check with clients in advance and manufacture products according to clients’request.

Insertion Loss & Return Loss Test


In telecommunications, insertion loss (IL) refers to the loss of signal power, calculated as a ratio in dB (decibel), resulting from inserting a device in a transmission line or optical fiber. It can also be referred to as attenuation, which indicates how much the signal loss is by comparing the input power to the output power.

A lower insertion loss value indicates a better insertion loss performance. For example, an insertion loss of 0.3dB is better than 0.5dB.

Return loss (RL) refers to the loss of reflected signal power. Therefore, the higher the return loss is, the lower the amount of reflection will be. Which means the fiber connector will have better performance with a higher value of RL.

HTD's connector is 100% tested with insertion loss and return loss before package. IL and RL data will be recorded on each patch cord's label.

3D Interference Test

3D interference test ensures that fiber optic connector end face's performance parameter is within IEC international standard range. The geometry of the end face/tip of fiber optic termini is a key factor for controlling the performance of the Fiber Optic connector. This geometry will determine which areas come into contact when two Fiber Optic connectors or termini are mated.

Measuring end face parameters such as the radius of curvature, the apex offset, and the fiber height during the polishing process provides both quality control and quality assurance. HTD's PC/UPC connector has over 90% 3D interference test passing rate. APC connector has over 85% passing rate. Below chart is for 3D inference test parameter reference.

Radius of Curvature10μm - 25μm7μm - 25μm10μm - 25μm7μm - 25μm
Apex Offset50μm 50μm 50μm 50μm
Fiber Height+50μm ~ -100μm +50μm ~ -100μm +50μm ~ -100μm +50μm ~ -100μm
Tilted AngleN/A8° + 0.5 / 0.3 N/A8° + 0.5 / 0.3

Visual End Face Inspection

Polished connector ferrules require visual inspection to find possible defects. This is accomplished by microscope machine which has a stage modified to hold the connector in the field of view. Fiber Optic Inspection Microscopes vary in magnification from 30 to 400 power, with 30-100 power being the most widely used range. Connectors are viewed end-on or at a small angle to find polishing defects such as scratches.

Class A Class B

Class A end face is the best quality level without any scratch. Class B end face is allowable for several scratches within certain micrometer (μm). HTD usually produce class A connector. However, if client requests class B connector with lower price, we can accept and produce as client wants.


Class A Standard

AreaArea RangeScratchSpot
A0~25 umNot AllowNot Allow
B25~115 umNot AllowNot Allow
C115~135um≦1um Allow 1 ; >1um Not Allow<1um Allow 1 ; >1um Not Allow
D135~250um≦2um Allow 2 ; >2um Not Allow≦2um Allow 2 ; >2um Not Allow

Class B Standard

AreaArea RangeScratchSpot
A0~25 umNot AllowNot Allow
B25~115 um≦2um Allow 3 ; >2um Not Allow<2um Allow 3 ; >2um Not Allow
C115~135um≦2um Allow 3 ; >2um Not Allow≦2um Allow 3 ; >2um Not Allow
D135~250um≦2um Allow 2 ; >2um Not Allow≦2um Allow 2 ; >2um Not Allow

As a large scale original manufacturer, HTD accepts OEM service requirement. More than half of our past orders contains OEM service. HTD has a great deal of experience in this.

Except OEM service, HTD also accepts clients’ customization in product itself. Usual product customization includes cable color, aramid yarn material, and sheath material.

Cable Color


If clients do not have demand, our cable colors go with usual ones. If clients have special demand, we can customize cable color. Clients need to provide color code to ensure color's exactness.

Aramid Yarn

If client does not have specific requirement in aramid yarn, we usually use nylon which is not flame retardant. If client wants aramid yarn material to be flame retardant, we can use Kevlar instead.


Inner/Outer Sheath

If client does not have specific requirement in sheath, we usually use PVC which is not flame retardant. If client wants sheath material to be flame retardant, we can use LSZH instead.


Product Parameter

If client does not have specific requirement in product performance parameters, we will follow the normal standard. If client has specific requirement, such as “tensile value has to be greater than 70 (normally is 50)”, client has to inform us clearly beforehand. We will strictly follow clients’ demand to produce their order.

In addition to the above, if client has demand in other customized conditions (package / logo etc.), we can communicate beforehand and satisfy your demand in our best.


HTD provides free sample to our clients. If you are new to us and want some sample for trial, you can request free sample from us.

Note: Free sample does not apply to all product, please contact us to check beforehand.

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HTD's production scale allows us to provide product to clients in relatively short time. If the order quantity is small (less than 10,000 pieces), our normal delivery time would be within 15 days after clients place their order.

If the order quantity is very large or the order requirement is complicated, our delivery time would be extended to 30 - 35 days after placing order.

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