Diagnostic Function - TM-11-5805-688-14-10186

T.O. 31W2-2GSC24-2

TM 11-5805-688-14-1

NAVELEX 0967-LP-545-3010

5-324. The overhead data from the overhead data

acknowledge signal MPSA from the OEG card sets the

multiplexer are applied to the output data multiplexer

positive stuff latch to produce positive stuff enable signal

during the bit 0 time of each word in the output data

MPSE, which is routed to the gated clock function, and

format. The total overhead message for one port during

signal MPSE-, which is applied to the address selector.

a minor frame uses bit 0 in each word in the following

When a negative stuff action is required, signal negative

format:

stuff acknowledge MNSA from the OEG card sets the

negative stuff latch to produce negative stuff enable

Words 1

Contain one of three 23-bitsynchronization

signal MNSE, which is routed to the gated clock

through

patterns used in the demultiplexer function.

function, and signal MNSE-, which is applied to the

23:

Each of the synchronization patterns, in turn,

address selector. When a no-action (no stuff required)

also contains one of the three stuffing codes

condition exists, neither latch is set. Therefore, the

in the demultiplexer overhead function.

overhead data multiplexer sequentially multiplexes the

appropriate PSC, NSC, or NAC stuff command, followed

Words 24

Contain 5-bit minor frame count for channel

by the appropriate minor frame code, to the output data

through

identification.

multiplexer.

28:

5-326. Diagnostic Function.

Word 29:

Contains overhead stuff sense bit when a

5-327. General. The diagnostic functional circuits

channel is processing a positive stuff code.

monitor the major signals on the card and produce one

of two diagnostic error signals (MDM- and MGC-) to the

5-325. The address selector provides the 3-bit address

display card when an error condition is detected. The

that selects the overhead data inputs to the overhead

diagnostic function is divided into two parts: the

data multiplexer. The absence of word count signal

composite error detection circuits, which produce

WC2429 enables the C input to the address selector

diagnostic data mux error signal MDM-, and the gated

during words 1 through 23, and the presence of the

clock error detection circuits, which generate diagnostic

signal enables the B input to the address selector during

gated clock error signal MGC-.

words 24 through 29. The C input provides one 3-bit

address code that selects the positive stuff (PSC) code,

5-328. Composite Error Detection Function (Figure

the negative stuff (NSC) code, or the no-action stuff

5-25). In normal operation, the minor frame activity

(NAC) code input that is applied to the overhead data

detector and the word 29 activity detector produce high-

multiplexer. The B input provides the 3bit address codes

level (no error) signals to OR gate U12. When the minor

that sequentially select the inputs that supply 5-bit minor

frame count signal (MFC1) or the word 29 signal (MW29)

frame count signals MFCO through MFC4 to the

from the format generation function is missing, the

overhead data multiplexer. The positive and negative

associated activity detector produces a low-level error

stuff latches provide two bits of the stuff codes applied to

signal to OR gate U12.

the C input of the address selector. The third bit is

permanently connected as a 1-bit input. When the need

for a positive stuff action is established, positive stuff

Change 1 5-85