AT&T DS1/DMi/ISDN-PRI manual 6SAMPLE Installation and Maintenance Problems, Transmission Facility

B-6SAMPLE INSTALLATION AND MAINTENANCE PROBLEMS

SYSTEM 75 OR SYSTEM 85 OPTIONS:

●D4 OR ESF FRAMING

●PER-CHANNEL SIGNALING

●ROBBED-BIT SIGNALING

● ZCS TRANSMISSION FACILITY

OTHER ENDPOINT OPTIONS:

●D4 OR ESF FRAMING

●PER-CHANNEL SIGNALING

●ROBBED-BIT SIGNALING

●ZCS

DS1 OR DMI

INTERFACE A

DS1 OR DMI INTERFACE B

24

TRUNKS

24 TRUNKS

CEM

CEM

24	DS1 OR DMI
TRUNKS	INTERFACE	A
24	DS1 OR DMI
TRUNKS
	INTERFACE	B

CEM OPTIONS: (BOTH ENDS)

●

●

BUNDLING SIGNALING OR

VARIABLE BIT-ROBBED SIGNALING

Figure B-6.Translation Effects on the CEM

Robbed-bit signaling (for a DS1) can be used either with variable bit-robbed signaling, or with bundling-mode signaling on both CEMs. For CEMs, the recommended or preferred signaling option is bundling.

A complex installation would involve a mixture of compressed and uncompressed channels. The CEM must be optioned for bundling-mode signaling to transmit digital data (AVD-type trunk groups). The switch translations must match one another to ensure an exact channel-to-channel correspondence. Voice-grade trunks (which are compressible) should be assigned to one DS1/DMI, while digital data trunks should be assigned to the other DS1/DMI. Figure B-7,Arrangement for a Complex CEM Installation, shows a complex CEM arrangement.