Mitel Voice Processing Solutions Installation And Service Manual

							El Digital Trunk Connectivity
On the receive side of the trunk, the Dual El trunk interface card demultiplexes the
voice, overhead, and signaling time slots to recover traffic data (voice information),
framing and error checking bits, and signaling data. It passes the PCM bearer
channels (with voice information) to the DSP 30 Digital Signal Processing line card
and signaling data (KM channel 16) to the SS7 Signal Processing card (Figure l-2).
MVIP BusChan 16
SS7 Data 1Channels l-15,17-31Traffic
11
II
II)Dual El Trunk
interface Card
El Trunks
II)r(SS7 link & voice
traffic)SS7 Signal
ProcessingCard
ISUPVoice Channelsto .,IFax Data,
El
Figure l-2
El Digital Trunk Connectivity CardsThe DSP 30 line card separates the voice data from the PCM frame and hands the
data off to the application running in the CPU.Similarly, the 
SS7 card separates the
ISUP information from PCM channel 16 and hands it off to the application running
in the CPU.
On the transmit side of the trunk, for outgoing calls (for example, to a help line) the
SS7 card assembles the ISUP data from the CPU for the Dual El Trunk Interface
card. Similarly, the DSP 30 line card formats the outgoing voice data. For
FaxMemo applications, the fax card fulfills the role of the DSP 30 line card but for
facsimiles.
Dual El Trunk Interface CardThe Series 6 Server Dual El trunk interface card is the interface for up to two El
2.048 Mbps CEPT digital trunks. The card conforms to CCITT Recommendation
G.704 for PCM 30 and to I.431 CCITT Recommendation: for ISDN. The
interface card, an AT bus-compatible adapter card, plugs into the Series 6 server
backplane in Model 70, Model 120, and Model 640 servers. The Dual El interface
card can be ordered to support either balanced (1 
OOQ standard 8-pin RJ-48C) or
unbalanced 
(75Q) trunk connections.
2l-4 
						

							El Digital Trunk Connectivity
Integration With Analog ‘Trunk InterfacesThe El Digital Trunk Connectivity feature may coexist with analog trunks in the
same Series 6 server module. In such configurations, the voice channel cards are mix
of DSP30 line cards (used in conjunction with the El trunks), and LC8 line cards
(used in conjunction with the analog trunks). The Dual El digital trunk interface
and the 
DSP30 line cards interconnect through the MVIP bus. Configuration and
line group assignments for both are handled through the Configuration Manager
(refer to TR 
1903 in the Technical Reference for configuration information).
Clock SynchronizationThe El clock can be synchronized to either to a clock recovered from the network
receive data 
(RxD) signal of one of the incoming trunks or an internal clock
reference (free-running master clock source on the Dual El card). Both El carrier
interfaces on the Dual El card recover a 2.048 
Mb/set clock ana 8 kHz frame clock
from their respective far end carriers.These recovered frame signals go to the 
on-card clock source for use to control the synchronization of the MVIP clock and
frame clock to the El 
RxD from the network.
An 
MVIP master clock is the actual source of the clock signals used by all cards
common to the MVIP bus. Only one master for each MVIP bus is allowed and only
one active 8 
kHz frame reference. The El clock default source is the MYII? master
on digital trunk interface card number 1, derived from the trunk 0 El 
RxD signal.
(that is, the only digital trunk interface card present in Model 70 and Model 1201
servers).(Trunk numbering is 0 through 3, starting with “0” on the first trunk card.)
Through the configuration manager, the reference source to the master clock is
selected offline. Sources include a free-running oscillator on the digital trunk
interface card and the network 
RxD signals (that is, from trunk 0 and trunk 1).
Clock reference switching switchover is “hitless,”that is, the clock reference can be
manually or automatically switched over to a second source without affecting traffic.
For digital trunk connectivity implementations where both trunks terminate in a
single Dual El Trunk Interface card, the Series 6 server provides automatic clock
source switchover in the event of trunk failure.On detecting a failure of the trunk
from which the clock source is derived, the Dual Trunk Interface card automatically
switches over to the second digital trunk (if the trunk in operation) on the card.
Because clock references are independent for each Series 6 server module, the Series 6
server can connect to different 
COs, a CO/PBX combination, or different PBXs.These different connections, however, must go to different Series 6 server modules
and must be the primary clock reference within their respective modules.
l-5 
						

							El Digital Trunk ConnectivityEl Digital Carrier EventsThe Dual El digital trunk interface card detects failures on the trunk receive data
(RxD).When failures persists for more than 200 milliseconds, the carrier alarm
function automatically generates a remote alarm to the far end in accordance with
CCITT Recommendations G.732 and G.733. For such failures, the carrier alarm
function informs the signaling function that circuits on a failed digital trunk are
unavailable and in-process calls are terminated. Only after a trunk is restored for 400
milliseconds are the circuits again made available. The system maintains for these
carrier events for each trunk:
0Loss of frame (LOS)
0Frame slips
0Bit errors
0Remote Alarms
0All one’s signal (AIS)
0Local carrier alarm
0Remote carrier alarm
aErrored seconds
0Failed seconds
When the server is online, service personnel can monitor several digital trunk
conditions and control several functions. These include:
0Displaying event counters, current trunk state, current clock source, and
trunk configuration for a single trunk or all trunks in a module.
0Setting the module clock reference.
0Connecting or disconnect a digital loopback toward the facility.
0Placing a digital trunk out-of-service. This action returns an AIS to the
switch.
0Restoring a digital trunk to service.
2
l-6 
						

							El Digital Trunk ConnectivityConfigurationDigital trunk connectivity configuration is done offline through the Physical
Resource Configuration Manager. Configuration for a Dual El card and for a
digital trunk connection consists of the following:
lSelecting the physical slot assignment for the card.
lSetting the module number in which the card is installed.
lConfiguring the I/O port address of the card
lSetting the signaling in use by the trunk.
lSetting the sequence number of the trunk.
lConfiguring the framing format
lConfiguring the coding format for the PCM bit stream.
Procedure CP 3 15 1 lists the steps for configuring a Dual El card.
Slot AssignmentThe Dual El Digital Trunk Interface card(s) are assigned (and factory-installed in)
specific physical slots in the Series 6 server backplane. The system software requires
these slot assignments to identify the hardware resources present in the backplane.
The configuration process for installing the digital trunk interface cards includes the
following:
1.Configure the cards (refer to TR 1906 in this volume).
2.In the Physical Configuration Menu, configure the slots assigned to the
cards.
3.In the Offline Menus, continue the configuration needed by the
applications.The factory installs the digital trunk interface card in these slots in the Series 6
Model 70, Model 120, and Model 640 servers:
Card
Model70Model 1201Model
120sModel640
Nnmber Slot NumberSlot NumberSlot NumberSlot Number
03669
1--811
1-7 
						

							El Digital Trunk Connectivity
The Model 70 and Model 1201 servers each support only one digital trunk for a
maximum system capacity of 
30 PCM voice channels. The Model 120s server and
Model 640 server each supports up to 
I20 PCM voice channels (ports) between two
digital trunk interface cards.
You assign the slot at the Physical Resource Configuration Menu for the card you are
configuring.
Module NumberThe module number is the Series 6 server module in which the digital trunk interface
card is installed. A four-module Series 6 Model 640 server can support a total
capacity of 240 
KM voice channels over 16 trunks.(In such a configuration the
line groups would be configured to use only part of the total number of PCM
channels available in each trunk. Refer to “El Connectivity Features” on page 3.)
You assign the slot for the card you are configuring at the Physical Resource
Configuration Menu.
Input/Output AddressThe digital trunk interface card can occupy one of two possible AT bus addresses:
Ox300h and Ox2300h where address Ox300h is the default address occupied by card 0
and 
Ox2300h is assigned to Card 1. These addresses can also be assigned to a
Smartcard in Model 
70 and 1201 servers. Before selecting the I/O address, check the
addresses occupied by these cards if they are present in the affected Series 6 server
module. If these cards are and either of their addresses are set to the same to which
the digital trunk interface card, an address conflict exists and bus contention will
occur. Ensure that each card is set to a unique address. The address selected in the
Select IO Address Menu must match the address for which the card is physically
jumpered.
Note:The digital trunk interface card has jumper positions for setting
interrupt request levels. However, the 
VoiceMemo application
polls the hardware to detect status and service the cards and does
not use hardware interrupt requests.
You set the card 
I/O address in the Configuration Menu for Board [DUAL El] in
AT slot x.
ij
1-8 
						

							El Digital Trunk Connectivity
SignalingThe Series 6 server supports only CCS for CCITT recommendations and ANSI
specifications for digital trunk connectivity. And, currently only SS7 (CCITT C7) is
supported as the signaling optional feature integration.Refer to the 
SS7 Integration
Manualfor complete information.
You set El trunk signaling in the Select Trunk Type Menu. The menu has options
for both analog and digital trunks. However, when you are configuring a digital
trunk interface card, the configuration manager accepts only the digital trunk
common channel signaling (CCS) option for El trunks.
Trunk ConfigurationTrunk configuration includes the trunk number, framing forma:, and coding format.
Trunk Sequence NumberThe trunk number is the logical number of the trunk, beginning with trunk number
0. You set the trunk number at the Configuration menu for 
Tl/El Carrier trunk x
Menu.
Framing Format
The 
VoiceMemo application supports CEPT framing and CRC framing. YOU select
the framing format the trunk uses at the Configure Frame Format for Board [DUAL
El] in AT slot x Trunk y Menu. The configuration manager accepts only the CEPT
and CRC framing formats.
Coding Format
The 
VoiceMemo application supports HDB3 (high density bipolar three) coding
formats for El trunks AM1 (alternate mark inversion) and. You select coding for the
trunk at the Configure Frame Coding for Board [DUAL El] in AT slot x Trunk y
Menu. The configuration manager accepts only CCITT-standard HDB3 or 
AMI(alternate mark inversion) for El trunks. 
(AMI, though available as an option, is a
less robust line coding technique than 
HDB3 and is not recommended.)
Clock SynchronizationThe system master clock can be synchronized either to the network (that is, a selected
El 
RxD signal) or to a free-running oscillator on the Dual El card. The digital
clock reference can be set to one of the following:
0Internal reference
0Network reference
0Default reference
1-9 
						

							El Digital Trunk Connectivity
The network reference is a selected El trunk. In the case of a Series 6 Model 70 or
Model 1201, the selected trunk will be trunk 0. In the case of Model 120s or Model
640, the selected trunk can be either 0, 
1, 2 or 3 (only one trunk can be selected).
The default reference is trunk 0.
The Series 6 server features automatic switchover to a backup clock source if the
primary fails. However, this feature functions only when both trunks of a Dual El
card are used and the clock is synchronized to the 
RxD signal of one of them..
Then, if the trunk to which the clock reference is derived, the Series 6 server will
automatically switch over to the second trunk on the Dual El card.
Note:This clock source switchover feature does not work if digital trunk
connectivity is split 
benveen two Dual Tl cards.
When configuring the system, use the network clock as the system clock reference to
prevent frame slips (Figure l-3). clock as the system clock reference
Series 6Server
Sync to Trunk
Figure l-3El Digital Trunk 
#3 -El Digital Trunk 
#4Switch
x1883vm6
Digital Trunk Clock Synchronization
Digital Trunk Online Maintenance
2l-10The 
VoiceMemo software features an online maintenance utility for monitoring
digital trunk activity and statistics (either individual trunks or all trunks), changing
the clock reference, removing trunks from service, and looping back trunks toward
the facility. Trunk activity includes the operational state of a trunk, 
errored seconds,
frame slips, and so forth. The display presents trunk status and the configuration of
the trunk-a useful feature for quickly validating trunk setup.
The information displayed is dynamic and changes as trunk status changes. For
example, if a trunk is taken out of service, the utility immediately reports it to the
display.Refer to the Centigram Series G Server Systems Diugnostics Manual for more
information. 
						

							2 Dual Tl Digital Trunk Connectivity
This chapter has a description and brief technical overview of the 
Tl digital trunk
connectivity available for Centigram Series 6 servers. It is provided both as an
introduction to the digital trunk connectivity feature and to provide planning and
installation guidance for retrofitting a Series 6 server with the feature.
Tl PCM Trunking OverviewThe Centigram Series 6 Communications Server includes 
Tl digital trunk
connectivity as a standard feature. This feature facilitates serverjntegration with
switches which predominantly use digital trunks for connection to the telephone
network and to special service equipment such as the Series 6 server. All Series 6
server products can be equipped with digital trunks.
The Model 70 and Model 
I201 both support only one Tl trunk, the Model 120sand each Model 640 module support up to four 
Tl trunks, configured to use all
trunk channels or fractional 
Tl (up to the maximum 60-port system capacity).
If you need an introduction to the 
Tl Digital Trunk Connectivity Feature of the
Series 
6 server for overall applications information, this section is written for you. If
you need an introduction to the 
Tl Digital Trunk Connectivity Feature as a general
review before configuring it or troubleshooting it, this section is also for you.
This section briefly reviews the structure of a 
Tl frame and the bit assignments for
channel associated signaling (CAS). It also discusses Series 6 
server/T1 applications,
Tl features, functional operation, alarms, and specifications. This section is not
intended to be a comprehensive discussion of digital trunking. For more
information on digital encoding of voice signals and digital transmission, refer to the
many external tutorials on the subject. Also, contact Customer Training for the use
of digital transmission by Centigram equipment.
Tl Digital Trunk MultiplexingWhen an analog voice signal is digitally encoded, it is periodically sampled to
produce an 8-bit representation (a “byte” or 
“octect”) of the sampled moment. This
sampling occurs at an 8 
l-&z rate (which equals 64 kb/s). After digital encoding,
each byte is added into a string of bytes encoded from other voice signals for
transmission over a common path. This “byte stringing” is done in an orderly
manner which repeats the insertion of a series of digitally-encoded voice signals, each
assigned to its own time-slot (“channel”) to produce frames. This voice data framing
is done in stages to assemble ever larger frames, beginning with a 
DSI frame. A DSl
i2-l 
						

							Dual Tl Digital Trunk Connectivity
frame has 24 
KM channels with 8 data bits in each time slot (channel) and,
including an extra bit as a start-of-frame marker 
193 bits makes up a completeframe.
Various framing formats have been developed for channel banks. All formats have a
framing bit in every 
193rd bit position.A unique bit pattern in the frame bit
position repeats every 12 frames to define a complete superframe (Figure 2-l). The
composite data rate of a frame is 1.536 Mbps. A f
raming bit precedes each frame (at
the same 8 
kb/s rate as the voice channels), increasing the frame rate to 1.544 Mbps.
A D4 superframe has a frame interval of 
1.5 milliseconds. VoiceMemo Release 6.OA
also supports the extended superframe (ESF) format of 24 frames each. ESF differs
from SF by the number of frames it contains (that is, 
24), the doubling of framing
(F) bits from a 
12-bit pattern to 24-bit pattern, and the addition of signaling bits C
and 
D used by channel associated signaling, known as “robbed bit” signaling” (refer
to Table 2-l and the following paragraphs).(I
nnetworks whtre ESF is not fully
implemented, the SF signaling bits are repeated.)
D4 and ESF are two of the formats for digital trunk connectivity feature that
VoiceMemo Release 6.OA supports. The standard D4 superframe format is known
by domestic 
RBOCs as the M24multiplexer format.
Table 2-ISF and ESF Signaling Bits
_i2-2Frame
Frame 6
Frame 12
Frame 18
Frame 24
Frame 30
Frame 36
Frame 42
Frame 48SF
A
B
A
B
A
B
A
BESF
AB
C
D
A
B
C
D 
						

							Dual T1 Digital Trunk Connectivity
D4 Super Frame
1.5 msbFrame Frame Frame Frame Frame Frame Frame Frame Frame Frame Frame Frame Frame Frame
\;\,,/I/
i\
r
JyyT,-y
nsbTerminal Framing 1
FT Bit (Odd Frames)0
Signalling Framing0
FS Bit (Even Frames)
FS Bit I.D.A
Figure 2-1
msb
10
0
11
BAB
Tl D4 Frame Map
m
msb
101
0
2-3