Symbol Indicators
This symbol designates the origination or the termination of a data path. The direction of the arrow connected distinguish the two data paths.
This symbol designates an invalid data path. If there is data present it should be ignored.
5.4 LOOPS AND PATTERNS
The following section describes the Test Modes used in the Model 1088. At the bottom of each Test Mode, a figure is included to show the data path.
Framer
Pattern | Loop | Line |
Gen/Det | Control | |
Processor |
| |
Loop Pattern
Control Gen/Det
Processor
Framer
Framer |
Figure 12. Block Diagram Local Loop Mode 1 |
| ||||
Pattern | Loop | Line | Loop | Pattern | Framer |
Gen/Det | Control | Control | Gen/Det |
| |
|
| ||||
Processor |
| Processor |
|
| |
Figure 13. Block Diagram Local Loop Mode 2
Local Loop
There are two different modes of operation for a Local Loop depending on the status of the units at the time that the Local Loop is initiated. If the units are not in linked (NS LED on) and the Local Loop is initiated, either by the front panel switch or the DTE inter- face, the unit will enter mode 1. If the units are linked, NS LED off, then the unit will enter a mode 2 Local Loop.
A Mode 1 Local Loop is shown in Figure 12. When the Local Loop is initiated, either by the front panel switch or the DTE interface, the loop will be activated within the local Processor. The data present at the local DTE interface will be looped back to the local DTE by the Loop Control block within the Processor. Any data present on
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