
VIU SETUP
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4-7
SIG-00-07-11 SEPTEMBER 2012 (REVISED OCTOBER 2019)
Version No.: B.2
Table 4-1 Aspect Codes Decoded By VIU
CODE
RULE
SOU RULE # N&W RULE #
CR RULE #
1
AN_CLEAR_TO_CP
N280a
2
AN_MEDIUM_CLEAR
N283
3
AN_CLEAR
301
281
N281
4
AN_APPROACH_LIMITED
N281b
5
AN_ADVANCED_APPROACH
303
282-A
N282a
6
AN_APPROACH_MEDIUM
N282
7
AN_APPROACH_RESTRICTED
306
8
AN_APPROACH
307
285
N285
9
AN_DIVERGING_CLEAR
304
283
10
AN_DIVERGING_APPROACH_DIVERGENG
283-B
11
AN_MEDIUM_APPROACH_MEDIUM
N283a
12
AN_DIVERGING_APPROACH
308
286
13
AN_RESTRICTING
309
290
N290
15
AN_STOP
310
292
N292
16
AN_TAKE_SIDING_INDICATOR
317
17
AN_MEDIUM_APPROACH
N286
18
AN_LIMITED_CLEAR
N281c
19
AN_APPROACH_SLOW
N284
20
AN_SLOW_APPROACH
288
N288
21
AN_APPROACH_DIVERGING
302
282
22
AN_SLIDE DETECTOR_WARNING_SIGNAL
N294a
23
AN_CLEAR_SLIDE_DETECTOR_SIGNAL
N294
24
AN_SLOW_CLEAR
287
N287
25
AN_APPROACH_DISTANT
285-A
25
AN_APPROACH_RESTRICTING
N293c
25
AN_NON_AUTOMATIC_BLOCK_APPROACH
312
294
26
AN_DIVERGING_APPROACH_RESTRICTED
306.1
27
AN_HOLDING_SIGNAL
318
28
AN_APPROACH CLEAR
N293b
28
AN_NON_AUTOMATIC_BLOCK_CLEAR
311
293
29
AN_DRAGGING_EQUIPMENT_INDICATOR
316
30
AN_ALL_DARK
31
AN_INVALID
4.5
PROCEDURE FOR CALCULATING A NEW UCN
The procedure for calculating a new UCN is provided below. This is typically an office procedure
but will be useful if vital parameter changes become necessary once units are in operation.
WARNING
CHANGING VITAL PARAMETERS REQUIRES CALCULATION OF
A NEW UCN FOR THE MODIFIED MCF. THIS SHOULD ONLY BE
PERFORMED BY AUTHORIZED PLANNING PERSONNEL. THE
LATEST VERSION OF THE DT UCN CALCULATOR SOFTWARE
MUST BE USED FOR THIS PURPOSE.
USER CONFIGURABLE ITEMS ARE UCN PROTECTED TO
PROHIBIT UNAUTHORIZED CHANGES.