ACS-160 Series & STL-160 Series T1 Mux Installation & Operation 6-Testing & Troubleshooting
Version 2.11, August 2011
6-6 Harris Corporation
Intraplex Products
6.3.3 Performance Data Review (RVU1 Group)
The functions in the RVU1 group (Table 6-4) provide status information on
● Phase-locked-loops.
● Input/output timing lock.
● Jitter buffer.
The items in the RVU1 group, unlike the items in the BLNK group, are always available for review. The
bi-level light located just to the right of the four-character function display on the CM-5RB module
indicates the state of each RVU1 function.
Table 6-4. RVU1 Group
Function Description
TxLk Transmit lock – The bi-level on/off light indicates the status of the T1 transmitter PLL.
For looped or external timing, if the top (green) light is on, the transmitter PLL is
locked. For internal timing, this light should be on all the time.
If the bottom (red) light is on, the transmitter PLL is not locked.
RxLk Receive lock – The bi-level on/off light indicates the status of the T1 receiver PLL.
If the top (green) light is on, the receiver PLL is locked.
If the bottom (red) light is on, the receiver PLL is not locked.
TxRx Transmit/Receive clocks – The bi-level on/off light indicates whether or not the transmit and
receive bus clocks are synchronized.
If the top (green) light is on, the transmit and receive bus clocks are synchronized.
If the bottom (red) light is on, the transmit and receive bus clocks are not
synchronized.
If the top (green) and bottom (red) lights are toggling on and off, the transmit and
receive signals are not synchronized, but their frequencies are close.
In this situation, each flash of the bottom (red) light corresponds to a relative phase
change of one T1 unit interval (UI) or about 648 nS. A relative phase change of one UI
is sometimes called a “bit slip.”
XsJt Excess jitter – The bi-level on/off light indicates whether or not the receiver jitter buffer depth has
been exceeded. The default buffer depth is 32 UI peak-to-peak (1 UI = 648 nS, so 32 UI = 20.7
microseconds).
If the top (green) light is on, the jitter buffer depth is exceeded (jitter >32 UI peak-to-
peak, assuming a factory default buffer depth).
If the bottom (red) light is on, the jitter buffer depth is not exceeded (jitter <=32 UI
peak-to-peak, assuming a factory default buffer depth).
To view the contents of the RVU1 group, perform these steps:
1. Press up or down on the GROUP switch until the display reads RVU1.
2. Press down on the SET/NEXT switch repeatedly to cycle through its contents.
3. To leave the RVU1 group, press up or down on the GROUP switch.
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