Cisco Systems IPMUX-1E operation manual Testing, Timing Modes

IPmux-1/1EInstallation and Operation Manual Chapter 1 Introduction

FXS/FXO/E&M

The TS assignment in a bundle with analog (FXS/FXO/E&M) is straightforward. Each timeslot in a bundle is assigned to a specific analog channel according to analog channel numbers; the first timeslot is assigned to the lowest analog channel that is configured, etc.

Note The E1/T1 TDMoIP gateway that works opposite the analog channels should work in Framed with CAS mode.

Testing

Diagnostic capabilities include E1/T1 or ISDN BRI S local and remote loopback tests for rapid localization of faults. The E1/T1 or ISDN BRI S channel can be looped locally, toward the line, or toward the remote end (see Chapter 4 for more information).

Remote Loopback and Tone Injection are available for the FXS/FXO/E&M port.

Timing Modes

The E1/T1 Tx clock, or ISDN/FXS PCM clock, can operate in several timing modes to provide maximum flexibility for connecting the IPmux-1/1E E1, T1, ISDN or FXS/FXO/E&M channels.

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 1-11,Figure 1-13, and Figure 1-14).

E1/T1

The E1/T1 available Tx modes are:

•Loopback Timing – the E1/T1 Tx clock is derived from the E1/T1 receive (Rx) clock.

•Adaptive Timing – in this mode, the E1 or T1 Tx clock is regenerated using the Adaptive method. In this method, the fill level of the buffer receiving packets is monitored. If the buffer begins to overfill, the regenerated Tx clock frequency increases to avoid overflow. If the buffer begins to empty, the Tx clock (toward the TDM device) decreases to avoid underflow.

•Internal Clock Timing – in this mode, the Tx clock is received from an internal oscillator.

•External Clock Timing – in this mode the Tx clock is taken from the external clock input (Ordering option). The external clock port also outputs the input clock signal to allow connection to other units, if needed.

Note In Adaptive Timing mode the regenerated clock is subject to network Packet Delay Variation and may not comply with jitter and wander specifications.

Functional Description 1-13