[j-nsp] attenuator

Aleksander Zawisza aleks at nortelnetworks.com
Wed Dec 31 14:49:25 EST 2003

It depends which Passport card you have. The 3-port ATM SM card has a mean
transmission power of -15 to -8 dBm, and the 2-port ATM IP SM card does -5
to 0 dBm. The cards have a max receive power equal to their max transmit

For the first card you should be ok with no attenuation at either end (but
you might still want to make sure each card receives ~3dBm below
saturation), for the second card you will need to put a 10 dB attenuator on
the Passport transmit.

If you have any more questions on the Passport side please reply off-line.



-----Original Message-----
From: Niels den Otter [mailto:otter at surfnet.nl] 
Sent: Tuesday, December 30, 2003 6:34 AM
Cc: juniper-nsp at puck.nether.net
Subject: Re: [j-nsp] attenuator


On Tuesday, 30 December 2003, LOM wrote:
> We have a Nortel Passport 7480 with STM1 single mode ATM interfaces,
> We will have 2 M7i Juniper in a very short time also they will have 
> OC3 Single Mode ATM2 interfaces,


SMIR optical interface
    * Connector: SC duplex connector
    * Length: maximum distance 9.3 miles / 15 km
    * Wavelength: 1,260 to 1,360 nm
    * Average Launch Power: -15 to -8 dBm
    * Receiver Saturation: -8 dBm
    * Receiver Sensitivity: -28 dBm

> We want to connect 7480 with M7i , as I didn't make a connection like 
> before that I want to ask if we should use attenuator
> between two interfaces. In single mode interfaces with 1-2 meter fiber 
> patch do we need attenuator ?

You need to find these specs for the Nortel Passport also and check if the
max launch power (-8 dBm for Juniper) stays within the receiver specs of the
other side (-28 / -8 dBm for Juniper).

-- Niels
juniper-nsp mailing list juniper-nsp at puck.nether.net
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