DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Architecture
1-32Protocols
1
The maximum user rate is 64 kbps for voice and data. The maximum
distances are based on T1 limitations. At 2.048 Mbps, each E1 frame
consists of 32 64-kbps c hannels
■
Analog
— A modulated voice-freq uency carrier sig nal
■
ADU Proprietary
— A signal generated b y an ADU. The signal is for
communication over limited distances and c an be understood only b y a
destination ADU or destination system p ort with a built-in ADU
■
Digital Signal Level 1 (DS1)
— A protocol defining the line coding,
signaling, and framing used on a 24-channel line. Many types of trunk
protocols (for example, PRI and 24th-chann el signaling) use DS1 protocol
at layer 1
■
European Conference of Postal and Telecommunications rate 1 (CEPT1)
— A protocol defining the line coding, sig naling, and framing used on a
32-channel line. Countries outside the Unite d States use CEPT1 protocol
Inside the system, data transmission ap pears in one of two forms:
1. Raw digital data, where the physic al layer protocols, like DCP, are
stripped at the inc oming port and reinserted at the outgoing p ort.
2. Pulse Code Modulation (PCM)-encoded analog signals (analog
transmission by a modem), the sig nal having been d igitized by an
analog-to-digital c oder/decod er (CODEC) at the incoming port.

Layer-2 Protocols

Layer-2 protocols are given b elow:
■
8-bit character c ode
—
Between the DTE equipment and the DCE
equipment. Depend ing on the type of eq uipment used, the cod e can be
any proprietary cod e set.
■
Digital multiplexed interface
proprietary — Family of protocols between
the originating DCE and the desti nation 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 Spe cification,
555-025-204
■
Voice-grade data
— Between the originating DCE and the d estination
DCE for analog transmission