CS62180 datasheet(46/50 Pages) CIRRUS

46 / 50 page

during the 6

th and 12th frames. The original LSB

of the channel is actually replaced with the sig-

naling data, hence this is known as "robbed-bit"

signaling. The 6

th and 12th frames can be treated

as one, 2-state channel, allowing a 2-state signal

to be updated twice every superframe. The two

frames can also be treated as separate channels

(A and B), yielding up to 4 separate codes for

each channel every superframe. For voice grade

applications, these signaling bits offer no notice-

able degradation in the signal quality. When

error-free data transmission is required however,

robbed bit signaling can be disabled (transparent

mode), and some other signaling facility must be

provided by the host system.

193E Framing Format

The 193E or Extended Superframe Format al-

lows much greater flexibility in both the use of

the framing bits, and the number of signaling

channels provided. As shown in Figure A6, the

framing bits are divided into 3 channels. The

FPS, or Framing Pattern Sequence, provides a

synchronization signal for determining frame and

superframe alignment. The FDL, or 4 kHz Facil-

ity Data Link, provides a dedicated channel for

system messages. The CRC (Cyclic Redundancy

Check) channel allows CRC check sums to be

transmitted with each superframe to monitor line

quality. As with the 193S format, every 6th

frame is designated as a signaling frame. The 4

signaling frames (6, 12, 18, and 24) can be mul-

tiplexed in different configurations to provide 2,

4, or 16-state signaling codes.

SLC-96

® Framing Format

The SLC-96

® T1 format is used between the Lo-

cal Digital Switch (LDS) and a SLC-96

Remote Terminal (RT). The framing format is a

SF(D4

®) superframe format with specialized

Data Link (DL) information bits. The DL bits

consist of Concentrator (C), Spoiler (S), Mainte-

nance (M), Alarm (A) and Protection Line

Switch (PLS) bits as shown in Figure A7.

T1DM Framing Format

The T1DM T1 format is used for DDS

® service

among hub and local intermediate DDS

® offices.

As shown in Figure A8, the framing format is a

SF(D4

®) superframe format with a specialized

channel 24 structure. The T1DM accepts up to

23 DS-0 signals and inserts one seven-bit byte

from each signal into the first twenty-three 8-bit

channel slots of the DS1 frame. The 24th chan-

nel slot contains a special synchronizing byte as

shown in Figure A9. DDS

® equipment insures

that every DS0 channel contains at least one "1".

Therefore, neither B8ZS nor bit-7 zero substitu-

tion should be selcted in the CS62180B.

193E

F-bits

Channel

bits

Signaling

Options

Frame

FPS FDL CRC

Data

Signaling

1-8

2C1

6C2

1-7

Bit 8

1-8

1-7

Bit 8

1-8

1-7

Bit 8

1-8

1-7

Bit 8

ABD

Figure A6. 193E Framing Format

CS62180B

DS225PP2

CS62180 Datasheet(PDF) 46 Page - Cirrus Logic

CS62180 Datasheet(HTML) 46 Page - Cirrus Logic

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Datasheet Download

Link URL