Lucent Technologies DEFINITY Enterprise Communications Server Release 6 Instructions Manual

DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-25 Protocols 
1
Layers
The Open System Interconnect (OSI) model for data communications contains 
seven layers, each with a specific function. Communications to and through the 
system concern themselves only with layers 1 and 2 of the model.
Layer 1, or the 
physical layer, covers the physical interface between devices and 
the rules by which bits are...

DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-26 Protocols 
1
Figure 1-9. Data Transmission States
DCE ORIGINATING
DCE DESTINATION  SYSTEM
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DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-27 Protocols 
1
Usage
The following is a list of the protocols when data is transmitted to and through the 
system. The list is organized by protocol layers. Refer to Figure 1-9
.
Layer-1 Protocols
Layer-1 protocols are used between the terminal or host DTE and the DCE, used 
between the DCE equipment and the system port, and used inside the system.
The...

DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-28 Protocols 
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 channels
nAnalog — A modulated voice-frequency carrier signal
nADU Proprietary — A signal generated by an ADU. The signal is for 
communication over limited distances and can be...

DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-29 Protocols 
1
Protocol States
Table 1-5 summarizes the protocols used at various points in the data 
transmission stream. See Figure 1-9
.
NOTE:
OSI means Open Systems Interconnect
PCM means Pulse Code Modulated
DMI means Digital Multiplexed Interface
Table 1-5. Protocol States for Data Communication
Transmiss-
ion TypeIncoming 
DTE to 
DCEOSI...

DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-30 Protocols 
1
Both the physical-layer protocol and the Digital Multiplexed Interface (DMI) mode 
used in the connection are dependent upon the type of 8-bit code used at layer 2 
between the DTE equipment and DCE equipment, as listed in Table 1-6
 and 
Table 1-7
.
Connectivity Rules
Figure 1-9 implies the following connectivity rules:
nOnly the DS1...

DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-31 Protocols 
1
nAlthough data entering the system through an EIA port has not been 
processed through a data module, the port itself has a built-in data 
module. Inside the system, port data is identical to digital line data. Data 
entering the system at a DCP line port can exit at an EIA port. Conversely, 
data entering the system at an EIA port can...

DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-32 Protocols 
1
This is because, through messaging, the terminating node knows the originating 
node cannot provide disconnect supervision. This messaging is not possible with 
non-DCS tie trunks, and the direct call is denied.
Some two-wire loop start trunks outside the United States provide busy tone 
disconnect in place of line signals. For these...

DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-33 Protocols 
1
Table 1-8. Protocols Used in DEFINITY 
Protocol ApplicationsMaximum 
Data Rate Maximum Distance
DCP Digital switch to data 
endpoints64 kbps 5000 feet (1524 m) for data
3000 feet (915 m) for voice
RS-232 System to administration
terminal. Data module to 
host computer 
Data module to printer
Data module for 
downloading and 
high-speed...

DEFINITY Enterprise Communications Server Release 6
Maintenance for R6r Volumes 1 & 2  555-230-126  Issue 2
January 1998
Maintenance Architecture 
Page 1-34 Protocols 
1
NOTE:
ADU means Asynchronous Data Unit
BCS means Business Communications System
MSA means Message Servicing Adjunct
ACU means Automatic Call Unit
Transmission Characteristics
The system transmission characteristics comply with the American National 
Standards Institute/Electronic Industries Association (ANSI/EIA) standard 
RS-464A...