Specifications

Installation and Operation Manual Chapter 1 Introduction
IPmux-24 Ver. 1.5 Functional Description 1-9
Testing
Diagnostic capabilities include E1/T1 local and remote loopback tests for rapid
localization of faults. The E1/T1 traffic can be looped locally, toward the line, or
toward the remote end (see
Chapter 6 for more information).
Timing Modes
IPmux-24 supports different timing modes to provide maximum flexibility for
connecting the IPmux-24 E1, T1 ports.
Each of the clocks must be configured correctly on both the receive and transmit
ends to ensure proper operation and prevent pattern slips (see
Figure 1-3 ,
Figure 1-4 and Figure 1-5 ).
E1/T1 Timing
Synchronization between TDM devices is maintained by deploying advanced clock
distribution mechanisms. The clocking options are:
• Loopback timing – the E1/T1 Tx clock is derived from the E1/T1 receive (Rx)
clock
• Adaptive timing – the E1/T1 Tx clock is regenerated from the network packet
flow and calculated according to arrival time of the incoming packets
• Internal timing – the Tx clock is derived from an internal oscillator
• External timing –the Tx clock is derived from the external clock input. The
external clock port also outputs the input clock signal to allow connection to
other units, if needed.
• In adaptive timing, the regenerated clock is subject to network packet delay
variation. That is why the quality of the adaptive clock depends on the quality
of the network.
• A special version of the device (IPmux-24/A), with an advanced clock recovery
mechanism, can be used in cellular backhaul applications.
System Timing
The IPmux-24 TDM links can be configured to use system clock, synchronized to
internal, loopback, external or adaptive timing source. The system clock has
master and fallback sources. If a fallback clock source fails, IPmux-24 switches to
internal timing.
Network Timing Schemes
The following paragraphs describe typical timing schemes and the correct timing
mode settings for achieving end-to-end synchronization.
Note