e Number:
6
Publication Date:
February 11, 2003
Document ID:
o02it000.fm
CONFIDENTIALITY NOTICE
The information contained in this document is the property of Positron Inc. Except as specifically
authorized in writing by Positron Inc., the holder of this document: 1) shall keep all information
contained herein confidential and shall protect same in whole or in part from the disclosure and
dissemination to all third parties, and 2) shall use same for operating and maintenance purposes only.
DISCLAIMER NOTICE
Although Positron Inc. has made every effort to ensure the accuracy of the information contained
herein, this document is subject to change without notice.
TECHNICAL CUSTOMER SUPPORT
Should a problem arise, contact your customer support department. If the problem cannot be resolved
by your support department or if you have any questions, contact Positrons Technical Customer
Support department at 1-888-577-5254.
© 2003 Positron Inc.
Teleline Isolator is a registered trademark of Positron Inc.
Product names, other than Positrons, mentioned herein may be trademarks and/or registered trademarks
of their respective companies. Contents
i
o02it000TOC.fm
1.
The Holding Coil Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.
Four-wire DX Signalling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.
DC Insertion on Two-wire Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.
Technical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.
Shelf Configurations for Tie-lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1
Three-card Shelf Configuration for Tie-lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.2
Five-card Shelf Configuration for Tie-lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.3
Eight-card Shelf Configuration for Tie-lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.
Service and Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
(26 pages)
Holding Coil Unit
1
7501-40
o02it001.fm
1.
The Holding Coil Unit
The Holding Coil Unit, model 7501-40, is used in conjunction with various
Teleline Isolator cards for four-wire DX signalling applications (four-wire
simplex DC current), as well as for DC simplex powering requirements (i.e.,
carrier). This type of signalling, also used by certain PBX tie-lines, is fully
described in this document.
Its features include the following: The unit provides a means of reintroducing DC voltage across the TX and
RX pairs of isolated DX signals. The unit is bi-directional and, therefore, the DC voltage source can originate
from the Station or Central Office (CO) side. The unit can be used to power a two-wire circuit from the Tip & Ring, using
an external power supply. 7501-40
2
Holding Coil Unit
2.
Four-wire DX Signalling
The TX and the RX pairs are used to create a third phantom pair which carries
the DC voltage.
For an illustration of four-wire DX signalling, refer to Figure 1.
Figure 1
Four-wire DX Signalling
When using the Teleline Isolator product to protect the line, one has to consider
that there are actually three pairs of signals which must be isolated across the TX
and RX pairs. This necessitates the use of three isolator cards. For an illustration
of the connections, refer to Figure 2. The TX data signal is isolated by the first Two-wire AC Data Card 7501-72,
and the RX data signal is isolated by the second. The DC voltage across the two pairs is accessible via a center tap on each of
the 7501-72 cards, and is routed to a DC Trip/DC Pilot Wire Card
(7501-15A,B, or C) or an OPX Card (7501-16A,B,or C) for isolation. With all signals isolated, three physical pairs come out of the Station side of
the shelf: one pair carries the TX data, the second carries the RX data, and
the third carries the DC voltage. The DC voltage must be put back across the TX and RX pairs, therefore, a
holding coil assembly is required.
TX PAIR
RX PAIR
DC VOLTAGE
SUBSTATION
CENTRAL
OFFICE Holding Coil Unit
3
7501-40 The entire scheme is bi-directional, therefore, the DC voltage source may
originate from the substation or the CO.
Figure 2
External Connections
T
R
T
R
R
R
T
T
T
T
R
R
HOLDING COIL
MODEL 7501-40
DC
ISOLATOR
CARD
MULTI-CARD
SHELF
TO CO CABLE
TX PAIR
C.T.
EQUIV.
ISOLATOR
CARD
7501-72*
C.T.
EQUIV.
ISOLATOR
CARD
7501-72*
TO
SUBSTATION
EQUIPMENT
RX PAIR
*A 7501-06A Carrier Card must be used instead of a 7501-72 for T1 carrier.
*A 751340 HDSL Card must be used instead of a 7501-72 for HDSL circuit. 7501-40
4
Holding Coil Unit
3.
DC Insertion on Two-wire Circuit
When a two wire customer equipment requires the DC voltage to be fed from the
Tip & Ring; it is possible to use the holding coil and an external power supply to
insert this DC on the line.
For an illustration of the necessary connections, refer to Figure 3.
Figure 3
Connections Using One Pair
When installing the circuit, care must be given to the following, The external power supply must be set to deliver the same voltage applied by
the CO equipment. You must make sure that the customer equipment does not draw more than
100mA. This is the maximum allowable current through the holding coil. If
necessary, use a resistor of sufficient power rating to limit the current. For
calculation purposes, the holding coil resistance is approximately 100
.
T Holding Coil Unit
5
7501-40
For this application there is no need to change the CO side jumper settings on the
backplane.
This circuit can be implemented in any slot of the shelves.
For information on wiring and installation, refer to Table 1.
Table 1
Holding Coil Wiring List: DC Insertion on Two-wire
Circuit
From: Station Cable
To: Holding Coil Cable
LABEL
LABEL
COLOR
Tip TB1-4
White/Orange
Ring TB1-10
White/Slate
From: Power Supply
To: Holding Coil Cable
LABEL
LABEL
COLOR
+
TB1-1
Blue/White
-
TB1-7
Brown/White
From: Holding Coil Cable
To: Station Equipment
LABEL
LABEL
COLOR
TB1-2
TIP
White/Blue
TB1-8
RING
White/Brown 7501-40
6
Holding Coil Unit
4.
Technical Specifications
For a listing of the units electrical specifications, refer to Table 2. For a listing of
the unitss physical specifications, refer to Table 3.
Table 2
Electrical Specifications (measured at 77°F or 25°C,
50% R.H.)
Table 3
Physical Specifications
Parameter
Specifications
INPUT VOLTAGE REQUIREMENT
None
POWER DISSIPATION
None
MAXIMUM SIGNAL LEVEL
+10 dBm with < 1% distortion
SIGNAL
Insertion Loss with 600 Termination (@
1000 Hz, 0 dBm)
0.2 dB maximum
Frequency response (300 to 3400 Hz)
± 0.2 dB relative to 1000 Hz
Flatness
1 dB from 100 Hz to 1 MHz
High frequency cut-off (-3dB)
3 MHz
Rolloff
-6 dB/oct from 3 MHz
Parameter
Specifications
Operating temperature range
-4°F to +149°F (-20°C to +65°C)
Height
7-1/2 (19.05 cm)
Width
4-3/8 (11.11 cm)
Depth
2-3/8 (6.03 cm)
Weight
1.42 lbs (0.646 kg) Holding Coil Unit
7
7501-40
5.
Shelf Configurations for Tie-lines
Tie-lines may be configured for use with the Three, Five or Eight-card Teleline
shelf. The three different types of tie-line configurations are described in the
subsequent sections.
5.1
Three-card Shelf Configuration for
Tie-lines
The Teleline Three-card Shelf, model 751127, is designed to accommodate one
tie-line circuit using the appropriate slots. This circuit uses slots 1, 2, and 3: one
7501-72 in slots 1 and 2, and one 7501-15A,B,or C (or 7501-16A,B,or C) in slot
3. For an illustration, refer to Figure 4. 7501-40
8
Holding Coil Unit
Figure 4
Tie-line Circuit: Three-card Shelf
The bottom back plane inside the shelf must be modified by reconfiguring the
strap option. For an illustration, refer to Figure 5.
THREE-CARD SHELF MODEL 751127
*A 7501-06A Carrier Card must be used instead of model 7501-72
for T1 carrier circuits.
TIE-LINE 1
7501-15X (OR 7501-16X)
7501-72*
S
L
O
T
1
S
L
O
T
2
S
L
O
T
3
*A 751340 HDSL Card must be used instead of model 7501-72
for HDSL circuits. Holding Coil Unit
9
7501-40
Figure 5
Bottom Back Plane Reconfiguration: Three-card
Shelf
For the tie-line circuit, the strap options are normally shipped with E2 and E3
jumpered, and they must be reconfigured to have E1 jumpered to E2 and E3
jumpered to E4.
When used in the strapped position, CO cable pairs for slot 3 should be
disconnected in the splice to remove the possibility of outside signalling being
introduced into the circuit.
To disconnect the cable pair for slot 3, W-G wires must be removed from TB1
terminals 6 and 12. For a view of the Three-card Shelf CO side terminal blocks,
refer to Figure 6.
THREE-CARD SHELF MODEL 751127
S
L
O
T
1
S
L
O
T
2
S
L
O
T
3
DEFAULT CONFIGURATION
TIE-LINE CONFIGURATION
E2
E2
E1
E1
E3
E3
E4
E4 7501-40
10
Holding Coil Unit
Figure 6
CO Side Terminal Blocks: Three-card Shelf
TB1
MALE CONNEC