Attenuator

Answered Question
Mar 12th, 2008

what's the purpose of putting an

attenuator between a MUX and CE?

We are seeing packet drops and suspecting

having the attenuator could be causing it

and planning to bypass the attenuator.

No errors at physical level

i need this urgently.

Thanks

I have this problem too.
0 votes
Correct Answer by tphelps about 8 years 9 months ago

Most OCn ports will use fiber. The only Cisco copper cards I am aware of are the EC1 and combo DS3EC1 card that provide an electrical STS-1.

Most SR and IR optics interfaces can be directly cabled regardless or cable length using no attenuation. LH/LX typically require an attenuator on short lengths.

As far as setting the TX power level, most are fixed an have an allowed range.

Provide some equipment info with a description of the connectivity and we can give you more detailed answers.

Correct Answer by Tom Randstrom about 8 years 9 months ago

"the access line should be using optic fibers,

right?what if it's using a coax cable?"

I am clear as to your network architecture.

"is one of the reason using an attenuator is

to protect the CE from the high power travelling accross the network?"

All termination equipment (whether fiber-, wireless-, or copper-based) has operating windows for receive power levels. If the incoming signal is too strong or too weak, the termination equipment will not operate as designed.

"could it be configured to match what is needed like, to higher the signal?"

Some equipment may have compensating circuity to adjust the incoming signal to meet the operating range. Some optical equipment has software controlled variable optical attenuators to adjust the input signals automatically.

I am not sure if I am answering your questions.

Correct Answer by Tom Randstrom about 8 years 9 months ago

An optical attenuator decreases the light level (the power) of the signal traveling over a network. It is used to adjust the optical signal level so the light hitting the optical receiving equipment fits into the operating range of the equipment. It is possible that the attenuator is of too great a value and the optical receiver in the attached device is not getting enough signal (light).

Correct Answer by tphelps about 8 years 9 months ago

Attenuators reduce the power of the signal. Think of it as sunglasses for the interface. To see if an attenuator is needed, measure the RX optical power with no attenuation and compare against the specs of the interface. If too high, attenuate. If not, don't. Also remember not to attenuate too much. Measure the RX power to see that the power level is not lower than the specs allow.

Always remember to clean and scope attenuators like you would with cables. Use caution.

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Correct Answer
tphelps Wed, 03/12/2008 - 11:23

Attenuators reduce the power of the signal. Think of it as sunglasses for the interface. To see if an attenuator is needed, measure the RX optical power with no attenuation and compare against the specs of the interface. If too high, attenuate. If not, don't. Also remember not to attenuate too much. Measure the RX power to see that the power level is not lower than the specs allow.

Always remember to clean and scope attenuators like you would with cables. Use caution.

Correct Answer
Tom Randstrom Wed, 03/12/2008 - 11:27

An optical attenuator decreases the light level (the power) of the signal traveling over a network. It is used to adjust the optical signal level so the light hitting the optical receiving equipment fits into the operating range of the equipment. It is possible that the attenuator is of too great a value and the optical receiver in the attached device is not getting enough signal (light).

jsheriony Wed, 03/12/2008 - 12:08

thanks guys.

both of you.

one more question.or three?

the access line should be using optic fibers,

right?what if it's using a coax cable?

is one of the reason using an attenuator is

to protect the CE from the high power travelling accross the network?

could it be configured to match what is needed

like, to higher the signal?

thanks again in advance

Correct Answer
Tom Randstrom Wed, 03/12/2008 - 14:04

"the access line should be using optic fibers,

right?what if it's using a coax cable?"

I am clear as to your network architecture.

"is one of the reason using an attenuator is

to protect the CE from the high power travelling accross the network?"

All termination equipment (whether fiber-, wireless-, or copper-based) has operating windows for receive power levels. If the incoming signal is too strong or too weak, the termination equipment will not operate as designed.

"could it be configured to match what is needed like, to higher the signal?"

Some equipment may have compensating circuity to adjust the incoming signal to meet the operating range. Some optical equipment has software controlled variable optical attenuators to adjust the input signals automatically.

I am not sure if I am answering your questions.

Correct Answer
tphelps Wed, 03/12/2008 - 15:49

Most OCn ports will use fiber. The only Cisco copper cards I am aware of are the EC1 and combo DS3EC1 card that provide an electrical STS-1.

Most SR and IR optics interfaces can be directly cabled regardless or cable length using no attenuation. LH/LX typically require an attenuator on short lengths.

As far as setting the TX power level, most are fixed an have an allowed range.

Provide some equipment info with a description of the connectivity and we can give you more detailed answers.

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