Juniper MX204 Hardware Guide

P
M
= 13 dB – 2 km (1 dB/km) – 5 (0.5 dB) – 2 (0.5 dB) – 0.5 dB
P
M
= 13 dB – 2 dB – 2.5 dB – 1 dB – 0.5 dB
P
M
= 7 dB
The following sample calculation for an 8-km-long single-mode link with a power budget (P
B
) of 13 dB
uses the estimated values from Table 22 on page 64 to calculate link loss (LL) as the sum of fiber attenuation
(8 km @ 0.5 dB/km, or 4 dB) and loss for seven connectors (0.5 dB per connector, or 3.5 dB). The power
margin (P
M
) is calculated as follows:
P
M
= P
B
– LL
P
M
= 13 dB – 8 km (0.5 dB/km) – 7(0.5 dB)
P
M
= 13 dB – 4 dB – 3.5 dB
P
M
= 5.5 dB
In both examples, the calculated power margin is greater than zero, indicating that the link has sufficient
power for transmission and does not exceed the maximum receiver input power.
CB-RE and RCB Interface Cable and Wire Specifications for MX Series
Routers
Table 23 on page 65 lists the specifications for the cables that connect to management ports and the wires
that connect to the alarm relay contacts.
NOTE: In routers where the Routing Engine (RE) and Control Board (CB) are integrated into a single
board, a CB-RE is known as Routing and Control Board (RCB). The RCB is a single FRU that provides
RE and CB functionality.
Table 23: Cable and Wire Specifications for Routing Engine and RCB Management and Alarm Interfaces
Router
Receptacle
Maximum
Length
Cable/Wire
Supplied
Cable
SpecificationPort
RJ-45 female1.83 m1.83-m length
with
RJ-45/DB-9
connectors
RS-232
(EIA-232) serial
cable
Routing Engine
console or
auxiliary
interface
65

Juniper MX204 Specifications

General

Cooling type	Active
Product color	Gray
Rack capacity	1U
Rack mounting	Yes
Number of fans	3 fan(s)
AC input voltage	100 - 240 V
Number of power supply units	2
Operating altitude	0 - 1828 m
Operating temperature (T-T)	0 - 55 °C
Operating relative humidity (H-H)	5 - 90 %

Weight and Dimensions

Depth	475 mm
Width	447 mm
Height	44.5 mm
Weight	10500 g