> What are the implications of using a GLC-ZX-SM module to light a > stretch of 20 - 30km? Would I need to add an attenuator, given that 20km is > well > below the 70km limit?
As always, the answer is "it depends", because it is the optical power, not distance, but usually if the link is <~25km you can expect to need an attenuator. The typical transmit is ~ 0-5dBm, and the max receive power is ~ -3dBm. If you overload the receiver, you could damage the device, or shorten is life, or cause various physical link errors to be reported as the optics is overloaded. So, in all cases, measure the received power, and add in the needed attenuation. Reference: http://www.cisco.com/en/US/prod/collateral/modules/ps5455/ps6577/product_data_sheet0900aecd8033f885.html Gary _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
