Nortel Networks 450 manual Table B-7 BASE-LX Receive Characteristics, Parameter Um MMF Um SMF Unit

Using the BayStack 450 10/100/1000 Series Switch

Table B-7. 1000BASE-LX Receive Characteristics (continued)

Description	Value	Units
Receive sensitivity	– 19	dBm
Return loss (minimum)	12	dB
Stressed receive sensitivity 1, 2	– 14.4	dBm
Receive electrical 3 dB upper cutoff frequency (maximum)	1500	MHz
Vertical eye-closure penalty 3	2.60	dB

1Measured with conformance test signal at TP3 (see IEEE 802.3, Clause 38.6.11) for BER = 10–12at the eye center.

2Measured with a transmit signal having a 9 dB extinction ratio. If another extinction ratio is used, the stressed receive sensitivity should be corrected for the extinction ratio penalty.

3Vertical eye-closure penalty is a test condition for measuring stressed receive sensitivity. It is not a required characteristic of the receiver.

Worst-Case Power Budget and Penalties

Table B-8 lists the worst-case power budget and penalties for the 1000BASE-LX models:

Note: The link power penalties (Table B-8) are used for link power budget calculations only. They are not requirements and are not meant to be tested.

Table B-8. Worst-Case 1000BASE-LX Power Budget and Penalties

Parameter	62.5 um MMF	50 um MMF		10 um SMF	Unit
Modal bandwidth as measured at	500	400	500	N/A	MHz · km
1300 nm (minimum, overfilled launch)
Link power budget	7.5	7.5	7.5	8.0	dB
Operating distance	550	550	550	5000	m
Channel insertion loss	2.35	2.35	2.35	4.57	dB
Link power penalties	3.48	5.08	3.96	3.27	dB
Unallocated margin in link power budget	1.67	0.07	1.19	0.16	dB

B-6 302401-D Rev 00