GTE Omni Si Database Technical Practices Issue 1 Manual

							TL-130500-1001
On four-wire trunks, the level change is performed by using
standard-level coordination pads. The values of the transmit
and receive analog pads (PT and PR, respectively) required
to adjust levels differ, depending on the loss plan implemented.
Also, under the VNLP, PR varies with the VNL of the trunk. Under
the FLP, PT is always 15.5 dl3 and PR is 7.0 df3 (Figure 36.9).
Under the VNLP, PT is always 13.5 
dB and PR is (VNL + 6.5) dB(Figure 36.3). In those cases where carrier terminals are not
collocated with the switching system, the pad values are reduced
by the four-wire facility loss and the loss of any impedance
matching equipment required.
Figures 36.5 through 36.11 provide typical circuit layouts and
losses for systems operated under the FLP.
Table 36.2FCL and VNLP Digital Pad Switching RulesCONNECTION
VNL + VNL + 4
SVR 5210
NOTES:
1. Trunk group 1 consists of PABX-CO, foreign exchange, and
class 5 WATS trunks.
2. Trunk group 2 consists of Tie and class 4 WATS trunk.
3. Under the VNLP, when the PABX-CO trunk has an ICL of less
than 2 
dB, a 2 dB pad is inserted when the PABX-CO trunk is
switched to a Tie trunk. If the PABX-CO trunk ICL exceeds 2
dB, no pad is inserted.
4.2s denotes a 2-dB switched pad.
6187 
						

							TL-130500-1001Table 36.3
ICL and FLP Digital Pad Switching Rules
IICONNECTIONDIGITAL PAD DIGITAL PAD
END ‘;;FD IcL(A) RECEIVE
(B) RECEIVE
(WNW
NOTES:
-7REMARKS
Transmission
Performance and
Testing Proceduress-3541. Trunk group 1 consists of PABX-CO, foreign exchange, and
class 5 WATS trunks.
2. Trunk group 2 consists of Tie and class 4 WATS trunk.
3. Gain and loss for two-wire trunks must be done in trunks by
changing strapping resistors.
36.4 This paragraph provides information on transmission
performance and testing procedures as they apply to the
systems.
The systems provide a means of switching two-wire and 
four-wire voice frequency facilities via a four-wire time-divided
pulse-code-modulated transmission medium. The systems
are designed to switch line circuits that have a nominal
characteristic impedance of 600 ohms, and trunk circuits that
have either a 
600- or 900- ohm characteristic impedance. All
systems are capable of direct digital interface to a DS-1 level
signal (D2 or D3 format) from a Tl-type repeater line.
8187SVR 5210 
						

							TL-130500-1001
0
0
0-2.0-3.2
-3.5
OMNI PABX
B PADClass 5 CO0.5
A PAD
!
1.2 dB
facility
t
0.3dB
Office
Loss
-3.5-3.0 0
0 --1.5
-0.30
Notes:1. Strapping resistors are changed to compensate
for the facility to obtain a 3.5 
dB circuit.
2.Digital pads are labeled A and B to Table 36.3
Figure 
36.5Line to CO Trunk Call (FLP)
The systems are designed to be installed as new PABXs orto replace existing installations. They may operate as main,
tandem, or satellite PABXs within a TTTN (Tandem Tie Trunk
Network), or as a main, satellite, or class SS3 PABX in a SSN
(Switched Services Network). Pad switching is digitally providedunder software control, enabling a four-wire Tie trunk to be
designated a nontandem, tandem, or intertandem trunk bychanging the data base. No hardware change is required to
upgrade or downgrade a four-wire Tie trunk. All tandem and
intertandem Tie trunks should be assigned to four-wire facilities.Non-tandem and satellite Tie trunks are strongly recommended
for four-wire design because transmission on universal service
connections is improved and because Tie trunks are often
upgraded as customer needs expand and the tandem Tie trunk
network grows.
SVR 52106167 
						

							TL-130500-1001-3.2
OMNI PABX
B PADvoice
Class 5 CO
0.5A PAD
-3.5-3.000-3.0+0.3-0.30
Note:Strapping resistors are changed to compensate
for the facility to obtain a 3.5 
dB circuit.
Figure 36.6Line to CO Trunk Call (FLP) with Voice Frequency RepeaterIf a system is intended to replace an existing analog PABX,
due to growth or feature enhancements, no special treatment
of trunks or facilities is required, assuming the trunks and
facilities were properly engineered for the analog PABX. The
PABXs provide pad switching, a station-to-station insertion
loss of 5.5 
dB, and 400-ohm to 400-ohm battery feed devices
for lines in compliance with latest industry recommendations.
Extended long loop line cards that have 
900-ohm line
impedance and 200-ohm to 200-ohm battery feed devices are
available. The PABXs have been designed to give a high grade
of service with excellent return loss and singing stability.
While the PABXs can operate under either the VNLP (Via Net
Loss Plan) or the FLP (Fixed Loss Plan) with no direct digital
interface, the FLP is required when a direct digital interface is
used. If a system is anticipated to grow and require direct digital
interface in the future, installation under the FLP is recommended
to avoid later adjustments and rearrangement. It should also be
noted that not all trunks are applicable to both the VNLP and FLP.
If there is a possibility that the system will change in the future
from the VNLP to the FLP, the trunks cards applicable to both
plans should be installed initially.
S-356
8187SW 5210 
						

							TL-130500-10010-0
Line
Card
OMNI PABX
B PADClass 5 COvoice frequency
repeater
PABX
cablecable-5.5 -5
00 --3.0+1.5-3.60
Notes:1. Strapping resistors are changed to compensate for the facility to obtain a 5.5 
dB circuit.
2. Digital pads are labeled A and 
8 to allow correlation to Table 36.3.
Figure 36.7Line to Nontandem Tie Trunk Call (FLP)
000+7-3.2
-3.5
OMNI PABXClass 5 CO
BPAD/-
; .Av 1 /1/-------
0.5A PAD0.3 dB
office
loss
-3.5-3.0 0
-0.30Note: Digital pads are labeled A and 
B to to allow correlation to Table 36.3.
Figure 36.8Line to CO Trunk Call (FLP) with Tl-Type Repeater Line
SVR 52108187s-357 
						

							TL-130500-10010.00
0-0.5+7-3.5
OMNI PABX
\B PAD 0.5 
’ PT
0.5A PAD
4-wire
trunk
card
tMain PABX 
office
-5.5-5.0 00+7-16-2 0
Notes:
1. Pads PT and PR are selected to obtain an FLP loss of 5.6 dB.2. Digital pads are labeled A and B to allow correlation to Table 36.3
Figure 36.9Line to Intertandem Tie Trunk Call (FLP)When a trunk group is provided on different facilities (i.e., direct
digital interface and physical facilities), the physical facilities
should be reviewed to ensure that proper transmission levels
will be achieved. Loading and/or line treatment should be
provided as required to avoid contrast between trunks and
subsequent customer complaints.
Test
Equipment36.5 No attempt has been made to specify a particular
manufacturer’s equipment type. However, this paragraph
does provide a list of recommended test equipment. Certain
tests require very precise measurements and the use of test
procedures or test equipment not equivalent to that specified
(wrong impedances, improper test method, etc.) will result in
errors. The following are examples of test equipment necessary
to perform the procedures given in this section:
l Models 4937A and 4938A transmission measuring set (Hewlett
Packard)
0 Transmission measuring set (Hekimian Laboratories)
l Model 
VH795G 600 ohm attenuator (Daven & Company)
0 Model 3581C frequency selective meter (Hewlett Packard)
e Model 4945A transmission impairment set (Hewlett Packard)
@ Model 9031 return loss measuring set (Wiltron)
l Model TTS-58A impulse noise test set (N. E. Electronics
Corp.)
0 Model T-207 longitudina! balance test set (Wilcom Products.
Inc.)
8 Model 3779D Primary Multiplex Analizer (Hewlett Packard)
SVR 5210 
						

							TL-130500-100100
0+7-3.5-5.5
OMNI PABXMain PABX
j Line
! Card
--------A 1IrMatrix
9+7 A- ,0 test
i0 level 
;
5d5i2 point 
:8 -16A---I\,
3
i-l
2s-5.5 -5
00 --16-2.00.0Note: Digital pads are labeled A and B to Table 36.3
Figure 36.10Line to Intertandem Tie Trunk Call (FLP) with Tl-Type Repeater Line
0-2.0+ 5.0 -5.2-5.5Main PABX
PABXClass 5 CO
B PAD
Tl -tyberepeater
line-------I .A PADITl -typerepeater
line
0.3
dBoffice
loss
-5.5-3.5+70-0-16-0.3Note: Digital pads are labeled A and B to Table 36.3
Figure 36.11Intertandem Tie Trunk to CO Trunk Call (FLP)
0.0
SVR 52108187s-359 
						

							TL-130500-1001Transmission
Performance
Specifications
Impedance
and Resistance
Insertion Loss
Frequency
Response
Level Tracking
Error
Signal to Distortion
(C-Notch)
S-36036.6 This paragraph lists the transmission specifications for the
OMNI SI PABXs. The specifications are for the PABX alone and
do not include any outside plant effects. Short lengths of cabling
(50 feet or less) from the PABX to an MDF (Main Distributing
Frame), or equivalent, are accounted for.36.6.1 Impedance and resistance are defined as follows:
0 Line circuit impedance: 600 ohms
0 Line circuit battery feed resistance: 800 ohms
0 Long loop line circuit impedance: 900 ohms
0 Long loop circuit battery feed resistance: 400 ohms
l Two-wire trunk circuit impedance: 900 ohms
0 Four-wire trunk circuit impedance: 600 ohms
* Four-wire trunk idle circuit termination: 600 ohms
36.6.2 The nominal insertion loss on any transmission path
through the 
OMNI SI PABX shall be 0.5 dB, referenced to 0 dBmat 1 KHz. This loss does not include the loss of digital pads that
are included on various path configurations. On 
station-to-station calls, an additional 
5-dB loss will be switched in, giving a
loss of 
.5 dB + - 0.5 dB. On calls involving trunks, digital pads
values of 0 
dB, 2 dB, or 3 dB may or may not be switched in as
the site engineering parameters dictate.36.6.3 Frequency response limits of any voice frequency path
(station-to-station, trunk-to-trunk, or trunk-to-station)relative to the 1 KHz insertion loss are as follows:
FrequencyResponse
204 Hz0 to + 5.0 
dB
304 to 3,004 Hz-0.8 to + 1 .O dB
3,204 Hz+ 1.5 dB maximum
3,404 Hz0 to + 3.5 
dBNOTE: + 
dB means more loss and - dB means less loss.
36.6.4 The maximum level error caused by the system from a
+ 3 to -50 dBm amplitude (1,004 Hz) input range is as follows:
Required Relative to
Input Levell-KHz Insertion Loss
+ 3 
dBm to -37 dBm+ -0.5 dB-37 
dBm to -50 dBm+-1.0 dB36.6.5 The C-notch signal to distortion ratio is as follows:
Input Level (100 
Hz)0 
dBm to -30 dBm
-40 
dBm
-50 
dBmSignal to Distortion Ratio33 
dB or greater
27 
dB or greater
22 
dB or greater
8187SVR 5210 
						

							Intermodulation
Distortion
(Four-Tone Method)
Single Frequency
Distortion
Envelope Delay
Distortion
SW 5210TL-130500-1001
36.6.6 This test method uses two sets of tones (one set at 856
and 863 Hz with a 
~-HZ spacing, and the second set at 1,374
and 1,385 Hz with an 11 -Hz spacing) that are applied
simultaneously to the path at a combined level of -10 
dBm with
the second and third order distortion products being measured.
The requirements are as follows:
l The second order distortion shall measure less than -45 
dB.l The third order distortion shall measure less than -45 
dB.36.6.7 Single frequency distortion is as follows:
Frequency of 0 
dBm0Input SignalMaximum Distortion
Power
Oto12kHz1.020 
kHz-28 
dBm0 (Note 1)
-40 
dBm0 (Note 2)
Notes:l For the given range of input frequencies, the output power in
any other single frequency shall not exceed the given power.
o The output at any other frequency from 0 to 4 KHz shall be less
than this power.
36.6.8 Envelope delay distortion measured on any path through
the system when referenced to 1,804 Hz is as follows:
0At604to3,004Hz,lessthan300vs.lAt404
to3,204Hz,lessthan550ps.The PAR (Peak-to-Average Ratio) reading will be 94. These
values are the corrected readings that have test holding and
battery feed configuration delays subtracted.
It must be kept in mind that the digital matrix has absolute delay
but does not have envelope delay distortion. The values listed
above indicate the envelope delay distortion of the line card, the
battery feed circuitry, the two-wire to four-wire conversion, and
the filtering applied prior to analog-to-digital PCM (Pulse Code
Modulation) conversion.In those cases where a direct digital
interface is used for trunking, the benefits of direct digital
interfaces become apparent in that the specifications listed
above apply from the station to the far end of the directly
interconnected PCM system. The far-end system must,
however, be compatible and capable of meeting published
D2/D3 delay specifications.
8/87S-361 
						

							TL-130500-1001Path Message
Noise36.6.9 Path message noise on any path through the system
should not exceed the following values:
l Message noise maximum: 23 dBrnC, 35 
dBrn 3KHz.
l Average: 18 dBrnC.
Path Impulse
Noise
The typical noise on any station-to-station path is in the 15 to
18 dBrnC range.36.6.10 Impulse noise on any path through the system should be
less than or equal to 5 counts in 5 minutes at the 
52-dBrnC
level.
Crosstalk
Attenuation36.6.11 The worst case crosstalk attenuation measured between
any two paths should be 70 
dB at 1,004 Hz relative to the sending
path level. Typical paths will exceed 75 
dB.
Longitudinal
Balance
Return
Loss
Lonaitudinal
Susceptibility
S-36236.6.12 Longitudinal balance attenuation of any line circuit or
trunk circuit when measured with the IEEE method, single port,
at 
ZM equal to 750 ohms, should be greater than or equal to the
following values:l
At204 Hz, 55 dB.
At1,004 Hz, 60 dB.
At3,004 Hz, 60 dB
36.6.13 The ERL (Echo Return Loss) and SRL (Singing Return
Loss) performance of stations and trunks is as follows:
0 Station-to-station: 26 dB ERL minimum and 18 dB SRL
minimum.l Station-to-trunk: 26 
dB ERL minimum and 18 dB SRL
minimum.
0 Trunk-to-trunk: 27 dB ERL minimum and 18 dB SRL
minimum.In the idle condition, all stations and trunks (except ground 
star-Uloop CO trunk circuits) will exhibit an SRL of better than 12 
dB.36.6.14 With a 
60-Rz longitudinal input current of up to 10 mA
or 50 VAC, the metallic noise measured on the T&R should be as
follows:
l 24 dBrnC or less for stations.
l 18 dBrnC or less for trunks.It may be difficult to achieve 10 ma of longitudinal current when
measuring trunk circuits that have a high longitudinal impedance.
These circuits should be tested with a longitudinal test voltage
from tip to ground or ring to ground of up to 50 VAC.
8187SVR 5210