Avaya Definity SI Maintenance Manual page 48

Maintenance Architecture
Analog
ADU Proprietary
communication over limited distances and can be understood only by a
destination ADU or destination system port with a built-in ADU
Digital Signal Level 1 (DS1)
signaling, and framing used on a 24-channel line. Many types of trunk
protocols (for example, PRI and 24th-channel signaling) use DS1 protocol
at layer 1
European Conference of Postal and Telecommunications rate 1 (CEPT1)
—
A protocol defining the line coding, signaling, and framing used on a
32-channel line. Countries outside the United States use CEPT1 protocol
Inside the system, data transmission appears in one of two forms:
1. Raw digital data, where the physical layer protocols, like DCP, are stripped
at the incoming port and reinserted at the outgoing port.
2. Pulse Code Modulation (PCM)-encoded analog signals (analog
transmission by a modem), the signal having been digitized by an
analog-to-digital coder/decoder (CODEC) at the incoming port.
Layer-2 Protocols
Layer-2 protocols are given below:
8-bit character code
equipment. Depending on the type of equipment used, the code can be
any proprietary code set.
Digital multiplexed interface proprietary
originating DCE and the destination DCE for digital transmission. See
DEFINITY Communications System and System 75 and System 85
DS1/DMI/ISDN PRI Reference, 555-025-101; and Digital Multiplexed
Interface [DMI] Technical Specification, 555-025-204
Voice-grade data
for analog transmission
1-12 Issue 4 May 2002
—
A modulated voice-frequency carrier signal
—
A signal generated by an ADU. The signal is for
—
—
Between the DTE equipment and the DCE
—
Between the originating DCE and the destination DCE
A protocol defining the line coding,
—
Family of protocols between the
555-233-123