Digital Monitoring Products Tellabs 242 Installation guide

Brand
Digital Monitoring Products
Model
Tellabs 242
Type
Installation guide
Description
These instructions are designed to help you install a Tellabs 242 Open Window Bridge in a central
station. The Tellabs 242 interfaces between the DMP SCS-1 Receiver and existing Direct Wire
or McCullough accounts. Incoming lines can have a maximum 2-wire line loss of 26 dB.
Equipment Needed:
Item Qty Tellabs Number Description
1) 1 24XA 19" rack mount card cage with 12 card slots
2) 1 4251A w/9952H Combiner amplifier w/ 2025, 2225 Hz filter
3) 1 4252A w/9952J Splitter amplifier w/ 1070, 1270 Hz filter
4) 1 8002A or 8007 2 Amp 48 VDC power supply
10 Amp 48 VDC power supply
5) * 4255S Quad termination module with sealing current
*Each 4255S provides a 2-wire hookup port for up to four DMP command processor panels. Up to ten 4255S
modules can be mounted in the Tellabs 24XA rack. This gives a total capacity of up to 40 monitoring ports
for each 24XA rack.
This equipment is manufactured by:
Tellabs, Inc.
4951 Indiana Ave.
Lisle, Illinois 60532
(708) 969-8800
Measuring dB levels
A small decibel meter capable of measurements to -60dBm is required to accurately adjust power levels on
the 2-wire lines. Use the DMP Model 550 dB Meter for taking measurements when installing the Tellabs
242 Open Window Bridge.
Direct Wire accounts connected to the bridge must have a DMP 1812, 1912, 1912XR, or XR200 Command
Processor panel installed at the end user's site.
McCullough accounts with two users on one loop must be divided into separate 2-wire runs to the central
station. Each McCullough account connected to the bridge must have a DMP 1812, 1912, 1912XR, or
XR200 Command Processor panel installed at the end user's site. An example of a proper McCullough
circuit is illustrated in Figure 2.
Installation Tellabs 242 Open Window Bridge
LT-0141 (2/99)
2500 N. Partnership Boulevard Springfield, MO 65803 www.dmpnet.com Digital Monitoring Products
2-wire line
Figure 2: McCullough loop with direct wiring
SCS-1
Receiver
2-wire line
Account #1
Account #3
2-wire line
Account #2
Tellabs
242
Open
Window
Bridge
Central Station
Figure 1: Original McCullough loop
Account #2
Account #1
Account #3
McCullogh Loop
Central Station
Direct
Wire
or
McCullough
Rack
Tellabs 242 Installation
2
Digital Monitoring Products www.dmpnet.com 2500 N. Partnership Boulevard Springfield, MO 65803
Open Window Bridge Installation
The physical installation of the bridge shall be in accordance with the practices and installation
procedures provided by Tellabs, Inc. This information shall be supplied by Tellabs when the bridge is
purchased. DMP provides a Multiplex Training and Troubleshooting guide (LT-0140) that explains the
various aspects of installation, setup, and operation.
When the DMP 1812, 1912, 1912XR, or XR200 Command Processor panel is installed at a site, the
2-wire line from the old Direct Wire, McCullough, or other 2-wire multiplex system is attached to its
multiplex jack. Each 2-wire line from a site can have a maximum line loss of 26 dB.
Each account is balanced by the bridge to provide continuous operation. The bridge attaches to the
SCS-1 receiver line card through a 4-wire bus. The receiver line card can communicate with up to 128
individual accounts. The SCS-1 Receiver has a capacity of five line cards attached to five bridges with a
total capacity of 640 multiplex accounts.
An illustration of the conversion follows:
Central Station
2-wire lines
Direct
Wire
or
McCullough
Rack
Account #1
Account #2
Account #3
Account #4
Figure 3: Original 2-wire
Central Station
2-wire lines Account #1
Account #2
Account #3
Account #4
SCS-1
Receiver
Figure 4: Converted 2-wire
Tellabs
242
Open
Window
Bridge
Tellabs 242 Installation
3
2500 N. Partnership Boulevard Springfield, MO 65803 www.dmpnet.com Digital Monitoring Products
DMP CONTROL
SCS-1
SCS-100
< -28.5dBm
4251A 4252A 4255S
IN
.5
1
2
4
8
16
IN
.5
1
2
4
8
16
IN
.5
1
2
4
8
16
IN
.5
1
2
4
8
16
A attn B attn C attn D attn
ADJUSTED FOR "B" ACCOUNT
GN
LS
0.1
0.2
0.4
0.8
1.5
3.0
6.0
DMP CONTROL
SCS-1
SCS-100
< -18.5dBm
4251A 4252A 4255S
IN
.5
1
2
4
8
16
IN
.5
1
2
4
8
16
IN
.5
1
2
4
8
16
IN
.5
1
2
4
8
16
A attn B attn C attn D attn
INITIAL SETUP
GN
LS
0.1
0.2
0.4
0.8
1.5
3.0
6.0
GN
LS
0.1
0.2
0.4
0.8
1.5
3.0
6.0
-9dBm> transmit
-9dBm> transmit
GN
LS
0.1
0.2
0.4
0.8
1.5
3.0
6.0
16.5dB Loss +
8dB roll-off =
-33.5 < 24.5dB Loss < -
9 trans-
mit
16.5dB Loss +
8dB roll-off =
-33.5 < 24.5dB Loss < -
9 trans-
mit
Digital Monitoring Products
2500 N. Partnership Boulevard Springfield, MO 65803 800-641-4282
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Digital Monitoring Products Tellabs 242 Installation guide

Brand
Digital Monitoring Products
Model
Tellabs 242
Type
Installation guide
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