AT&T DS1/DMi/ISDN-PRI manual D4-Channel Banks, Sample Installation Maintenance Problems

SAMPLE

INSTALLATION

AND

MAINTENANCE

PROBLEMS

B-7

SYSTEM 75 OR SYSTEM 85

OTHER ENDPOINT

INTERFACE

A OPTIONS:

INTERFACE A

OPTIONS:

●

D4 OR

ESF

FRAMING

●

D4 OR

ESF FRAMING

●

PER-CHANNEL SIGNALING

●

PER-CHANNEL

SIGNALING

●

ROBBED-BIT

SIGNALING

●

ROBBED-BIT SIGNALING

●

ZCS

TRANSMISSION

FACILITY

●

ZCS

12 AVD

DS1 OR DMI

12 AVD

DS1

OR DMI

INTERFACE

A

TRUNKS

TRUNKS

INTERFACE A

21 VOICE-

CEM

CEM

21

VOICE-

DS1 OR DMI

DS1

OR DMI

GRADE

GRADE

INTERFACE

B

INTERFACE B

TRUNKS

TRUNKS

SYSTEM 75 OR SYSTEM 85

OTHER ENDPOINT

INTERFACE B OPTIONS:

INTERFACE B

OPTIONS:

●

D4 OR

ESF

FRAMING

●

D4 OR

ESF FRAMING

●

PER-CHANNEL SIGNALING

●

PER-CHANNEL SIGNALING

●

ROBBED-BIT

SIGNALING

●

ROBBED-BIT SIGNALING

●

ZCS

●

ZCS

CEM OPTIONS:(BOTH ENDS)

●BUNDLING SIGNALING

●SELECTED COMPRESSED CHANNELS

●SELECTED UNCOMPRESSED CHANNELS

●NO SIGNALING ON AVD TRUNKS SINCE THEY ARE ON THE 24TH CHANNEL

●THE SECOND DELTA CHANNEL (CHANNEL 24) FOR THE 12 AVD TRUNKS MUST BE SHIFTED PER STANDARD CEM OPTIONS TO CARRY THE 24TH CHANNEL INTACT

Figure B-7.Arrangement for a Complex CEM Installation

NOTE: Although it is possible to mix compressed and uncompressed channels with the variable bit-robbed signaling option installed in the CEM, this arrangement is not recommended because the compressed channels are restricted to analog data. Bundling signaling is always the recommended option.

D4-Channel Banks

The D4-channel banks used with System 75 and System 85 networks require simple translations. However, there are pitfalls. The D4-channel banks use individual plug-in circuit packs for each channel (trunk interface). System 75 or System 85 DS1/DMI connected to a D4-channel bank must be compatible with those installed plug-in channel units. It is recommended that unused channels (in a System 75 or System 85) be placed in an unused (dummy) trunk group. Figure B-8,System 75/System 85 to a D4-Channel Bank, shows a System 75/System 85 connection to a D4-channel bank.