Specifications

Chapter 1 Introduction Installation and Operation Manual
1-12 Functional Description IPmux-8/16 Ver. 6.00
• Internal clock – the Tx clock is received from an internal oscillator.
• External clock (IPmux-16 only) – the Tx clock is taken from the external clock
input (ordering option). For CT3, there is an additional option to take the
timing from an internal T1 line, as long as this T1 port is in adaptive mode. The
other T1 lines can take their timing from this T1.
• E3/T3 cannot use external clock as a clock source.
• The input signal on the external clock port is repeated and is available on the
TD outputs in order to allow feeding other devices with the clock source signal.
• The output clock in the external clock port is not locked on the input clock. This
is why RAD does not recommend using a concatenated cable to daisy chain the
clock.
Each of the clocks must be configured correctly on both the receive and transmit
ends to ensure proper operation and prevent pattern slips.
The following paragraphs describe typical timing schemes and their correct timing
mode settings in order to achieve end-to-end synchronization.
External Network Timing
E1/T1
When an external network is used to synchronize the E1/T1 devices, all the
IPmux-8/16 units should be configured to work in loopback mode (see
Figure 1-9).
This topology enables any-to-any connectivity; in
Figure 1-9 all three IPmux-8/16
units have direct E1/T1 connectivity. In this timing configuration both mesh and
star bundle connection topologies are supported.
Figure 1-9. IPmux-8/16 in Loopback Timing Mode – E1/T1
External timing from the network can also be issued to IPmux-8/16 by external
clock input; in this case the E1/T1 device will use LBT mode (see
Figure 1-10).
Notes