Figure 7: Master And Secondary Clock Settings (Top View); Table 10: Frequency Off-Set By Clock Type - Motorola Canopy T1/E1 User Manual

Canopy T1/E1 Multiplexer
Frequency Off-set
Clock (accuracy over 24
Type
Stratum 1
Clock
Stratum 2
Clock
Stratum 3
Clock
Stratum 4
Clock
The Canopy T1/E1 Multiplexer does not have an internal oscillator. Therefore, the unit
must be synchronized to a T1/E1 bit stream in order to accurately pass T1/E1 traffic. The
Canopy T1/E1 Multiplexer may be configured to synchronize to a near-end or far-end
Canopy T1/E1 Multiplexer.
Master and Secondary Clocks
The clock on each Canopy T1/E1 Multiplexer must be correctly configured to prevent
frame slips. Each of the four (4) T1/E1 ports may be configured as the Master clock
source or the Secondary clock source. Any port may be set to Master and any port may
be set to Secondary, however there may only be one (1) Master and one (1) Secondary
clock setting per unit.
Note: If neither the Master or Slave port is active, then the system will start at Port 1 and
search in logical order until it finds an active T1/E1 port, at which time it will assume this
to be the Master clock source.
Two scenarios are shown below, one scenario with Port 1 set to Master and Port 2 set to
Secondary. The second scenario shows Port 1 set to Secondary and Port 3 set to
Master.

Figure 7: Master and secondary clock settings (top view)

Issue 3

Table 10: Frequency off-set by clock type

Time to First
hours) Frame Slip
-11
1 x10 1 every 72 days
-10
1x10 1 every 3.5 hours
-7
3.7x10 1 every 6 minutes
or
255 in 24 hours
-6
3.2x10 Up to 1 frame slip
every 4 seconds in
free-run
Page 22 of 73
T1/E1 Multiplexer FPGA Version 3.4
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September 2004
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