AT&T 7500 series, 7100 series, 2500 series, 7200 series, 7400 series, 7300 series manual Circuit Packs

1-10TRANSMISSION STATES

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Table 1-2.Trunk Port Types

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⎜

⎜

Circuit Packs

⎜

⎜

⎜

⎜

⎜

__________________________________________________________

⎜

⎜

⎜

⎜

⎜

⎜

Signal

⎜

Type

S85/G2

⎜

⎜ DIMENSION

⎜ S75/G1

⎜

⎜

⎜

⎜

⎜

_

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜ Traditional

⎜

⎜

Universal

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜ Module*

⎜

⎜

⎜

⎜ Module

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

Analog

CO

⎜ LC08

⎜ TN747B

⎜ SN230B

⎜ TN747B

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜ Auxiliary

LC13

TN763C

SN231

⎜ TN763B

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜ DID

⎜ LC09

⎜ TN753

⎜ SN232B

TN753

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

Tie

⎜ LC11

⎜ TN760C

⎜ SN233C

⎜ TN760C

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜ Digital

⎜ DS1

N/A

TN767

ANN11E

⎜ TN767

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜ PRI

⎜ N/A

⎜ TN767

⎜ ANN35

TN767 and

⎜

⎜

⎜

⎜

⎜

⎜

⎜

TN555

⎜

⎜

⎜

⎜

⎜

⎜

⎜

⎜

*Universal modules are available only on the G2 switch.

∙From a digital switch, the voice signal, which is represented in the switch as digital PCM code, is converted to analog via a codec built into the analog line or trunk circuit pack.

∙From an analog switch, conversion of the internal PAM code to continuous analog signals also occurs at the trunk or line port.

For outgoing or tandem calls that are routed over digital trunks, and for intercom or incoming calls to digital terminals, the following processes occur:

∙From a digital switch, PCM code treatment depends upon the port through which the signal exits.

—DS1 and primary rate interface (PRI) ports package the signal according to how the port is administered. (The line coding, framing, and signaling are administrative choices. Refer to the Multiplexed Communication section of this chapter for further details.) In addition, PRI ports package their supervisory messages according to ISDN-PRI protocol.

—Digital-line ports (System 75 and Generic 1) and general-purpose ports (System 85 and Generic 2) are both digital ports that package the signal according to DCP protocol. (See page 1-13for an explanation of this protocol.)

—Basic rate interface (BRI) ports are digital ports that package the signal according to ISDN BRI protocol. (See page 1-13for an explanation of this protocol.)

∙From an analog switch, no provision is made for connecting with digital voice terminals. Outside the switch, however, outgoing and tandem calls can be packaged for transmission over digital trunks. The voice signal exits the switch via analog trunks, then enters the digital trunk at a D4 channel bank. (See the Multiplexed Communication section of this chapter for further details.)