User's Manual

110 LEDR Series I/O Guide MDS 05-3627A01, Rev. D
Transmit Clock Selection (Subrate Models Only)
The transmit clock selection must be addressed for every radio in a sub-
rate radio system installation. The single most important consideration
is that there be only one master clock in a subrate radio network. The
master clock can originate from the radio or from the Customer Pre-
mises Equipment (CPE).
The radio is capable of several different clocking modes. Refer to
Figure 24 on Page 110 for typical system clocking methods.
Refer to the Clock Mode screen description on Page 35 for setting the
radio transmit clocking from the front panel. Refer to the
clkmode
description on Page 57 for setting the radio transmit clocking mode from
the
CONSOLE Port.
NOTE: When customer premises equipment (CPE) is operated in
looped clock mode, it is recommended that the radio not be set
to line clock mode. To do so may cause the transmitting
radio’s PLL to be pulled out-of-lock, especially when oper-
ating at 4E1 data rates.
Invisible place holder
Figure 24. Typical Repeater Clocking Arrangement
(no multiplexer at repeater site)
CPE
REPEATER NULL-MODEM
DATA INTERCONNECT CABLE
ETHERNET CROSS-CABLE
REPEATER SITE
CPE
SITE A
SITE B
SITE C
LEDR Radio
Clock Source: Ext. TX
LEDR Radio Clock
Source: Ext. TX
LEDR Radio
Clock Source: Looped
Network or
Internal Clock
External Mode
Scenario 1:
LEDR Radio Clock
Source: Internal
Scenario 2:
Scenario 1:
Scenario 2:
External Mode
LEDR Radio Clock
Source: Ext. TX