Telex 1505 User Manual
1505 Audio Line Driver
CH 1
CH 1
Tx
Rx
MIC
SPEAKER
CH 2
CH 2
CH 3
CH 3
CH 4
CH 4
Service Manual
1505 M IXER/
LINE DRIVER
CH 1
CH 2
MUTE
CH 3
CH 4
SPKR
PTT
HANDSET
MIC
SPEAKER
CH 1
CH 2
Tx
CH 3
CH 4
CH 1
CH 2
Rx
CH 3
CH 4
LEVEL ADJUST
098-0355
Table of Contents
1. General ........................................................1
2. Standard Features ................................................1
3. Installation ......................................................1
4. Connections .....................................................3
5. Operation .......................................................5
6. Theory of Operation ..............................................7
7. 1505 Specifications ...............................................10
8. Parts List ......................................................11
1. General
The Vega Model 1505 Audio Line Driver is a
general purpose card that provides a reliable
means of remotely controlling a variety of cus
tomer specified devices. The card is flexible. It
can perform basic switching functions, custom
ized switching functions (via jumpers), or spe
cial user-defined functions. It plugs into a
Tellabs Type 10 or equivalent open frame rack
and can be used in conjunction with any remote control console.
2. Standard Features
•
Four balanced line inputs, switchable
•
Four single-ended inputs, switchable
•
One microphone input from front panel or
connector
•
Jumper options for carbon, electret, or dy
namic microphone elements
•
Four balanced 600-ohm line outputs
•
One-watt eight-ohm speaker output
•
12 Vdc operation
•
All receive inputs can be individually muted
by rear panel switch low inputs
2.1 Optional Features include:
•
Jumper-selected receive input compression
•
User switch-programmable mixing function,
for example one input can be switched to
any or all outputs
•
Jumper selectable 600 ohm or 10K ohm high
input impedance
3. Installation
Caution - ESD Sensitive
-
This piece of electronic equipment con
-
tains electronic components known to be
-
-
susceptible to Electro-Static Discharge
(ESD). Precautions have been taken to
avoid the effects of ESD, however the user
is encouraged to promote safe handling
techniques in the handling, storage and
service of this equipment.
3.1 Introduction
Only experienced technicians familiar with
similar types of equipment should attempt to
install the 1505. Only basic hand tools are required to remove the card, change jumper set-
-
tings, connect phone, signal, and power lines.
Read this section thoroughly before attempting
to install the card. Exercise care to prevent wir
-
ing errors and equipment damage.
3.2 Inspection
Carefully unpack the equipment and inspect it
thoroughly as soon as possible after delivery. If
any part of the equipment has been damaged in
shipment, report the extent of the damage to
the transportation company immediately.
This unit has been inspected and adjusted to its
recommended operation condition at the fac
tory. Unless it has been handled roughly in
shipment, abused or tampered with, it won’t re
quire further adjustments. Simply make the in
stallation connections as described in the fol
-
-
lowing sections.
1
3.3 Mounting
This card is intended to be mounted in a
Tellabs Type 10 or equivalent open frame rack.
To avert erroneous operation, don’t install the
card adjacent to equipment that generates high
temperature or electromagnetic radiation. Al
ways provide an appropriate service loop on in
terconnecting cables.
3.4 Access for Installation/Servicing
When installing into a Tellabs Type 10 or
equivalent open frame rack, ensure the front
and rear of the rack have clear access for card
installation and wiring.
-
-
To service, remove the 1505 from the rack or
place on a circuit card extension for access
while troubleshooting.
3.5 Power
Primary power for the card is a regulated
source of 12 Vdc.
Figure 1. 1505 Component Location
2
4. Connections
Warning - High Voltage! Remove
Power Before Servicing!
High voltage may be present on this card (if
used for switching phone lines with super
imposed dc current signaling) which could
cause serious injury or loss of life. Only
qualified personnel familiar with this type
of circuitry should work on this equipment.
To prevent injury, damaging the card or
other equipment, remove power before
making connections.
4.1 Power connections
Connect positive 12 Vdc to pins 55 and 56.
Connect the 12 Vdc return (normally ground)
to pins 39 and 40. For best performance, use at
least 20 AWG or larger wire for power connections.
4.2 Signal Connections and Card Edge Con
nector Pin Assignment
Refer to the schematic and Table 4 (shows the
1505’s pin assignments and has a blank for any
-
customized functions that might be configured)
for the appropriate pin number to make connec
tions. Use at least 24 AWG wire for signal
connections.
4.3 Special considerations for optional wiring
4.3.1 Receive Compressor/Limiter Jumpers
Each receive channel has a compressor/limiter
circuit which helps provide a consistent audio
level. If some external equipment already in
cludes compressor/limiters, these circuits may
be bypassed by changing the associated
jumper’s position. For example, moving JP6
from the “A” (in) to the “B” position (out) bypasses Rx Ch #1’s Compressor/Limiter. Refer
to Table 1 and the schematic for the appropriate jumper selection.
JP# Function Jumper Status Notes
In Out A B
1 Mic PTT/Speaker Mute Coupled Separate N/A N/A PTT mutes Speaker
2 Mic, Carbon Element In - N/A N/A
3 Mic, Electret Element In - N/A N/A
N/A Mic, Dynamic, High Out - - N/A N/A JP2, 3, 4 out
4 Mic, Dynamic, Low Out In - N/A N/A
5 Mic, Comp./Lim. N/A N/A In Bypass
6 Rx Ch #1 Comp./Lim. N/A N/A In Bypass
7 Rx Ch #2 Comp./Lim. N/A N/A In Bypass
8 Rx Ch #4 Comp./Lim. N/A N/A In Bypass
9 Rx Ch #3 Comp./Lim. N/A N/A In Bypass
10 RX Ch #3 600Ω/10ΚΩ 600Ω 10ΚΩ Ν/Α Ν/Α
11 RX Ch #1 600Ω/10ΚΩ 600Ω 10ΚΩ Ν/Α Ν/Α
12 RX Ch #4 600Ω/10ΚΩ 600Ω 10ΚΩ Ν/Α Ν/Α
13 RX Ch #2 600Ω/10ΚΩ 600Ω 10ΚΩ Ν/Α Ν/Α
Table 1. Jumper Options
3
4.3.2 Microphone Jumpers
Depending on which microphone you are us
ing, the following jumpers must be installed:
JP2 - carbon element; JP3 - electret element;
JP4 - dynamic element with a low output.
No jumpers are installed for a dynamic micro
phone with a high output.
4.3.3 Receive Line Input Impedance
A 600Ω terminating resistor is provided for
each receive line input. Refer to the schematic
and Table 1 for the proper jumper installation.
4.3.5 Parallel Transmit Line Impedance
-
Matching
If the occasion arises where the transmit line
output must operate in parallel with another
line terminating device, an impedance mis
match to the phone line will result. To maintain
ate a resistive pad on the output of the 1505
a 600Ω termination, it will be necessary to cre
-
line driver. A similar pad must be installed in
each parallel device. This resistive pad creates
a matching network with the phone line, how
ever it induces a loss in the transmission path
which lowers the line level and may affect the
ultimate performance.
4.3.4 Switch Settings
Switches S1 to S5 provide the means to pro
gram the signal inputs to the output circuits.
Any input can be programmed to any output.
Multiple inputs can be combined to a single
output, or conversely a single input can be programmed to one output. Refer to the schematic
and Table 2 for the proper jumper installation.
Refer to the schematic and Table 2 for proper
switch closures.
-
In order to easily insert the pad, a provision has
been made in the circuit to allow the user to al
ter the value of two resistors in the transmit
line output. The 1505 is shipped from the fac
tory for single line termination without a pad,
resulting in the balanced transmit line output
having a 0 Ω resistor in each leg of the transformer without loss. To add the pad, both 0 Ω
resistors must be replaced with a value corresponding to the number of parallel lines. Refer
to the schematic and Table 3 for proper resistor
values and corresponding insertion loss.
Table 2. Output Programming Switch Settings/Associated Switch
Input Outputs
Tx Ch #1 Tx Ch #2 Tx Ch #3 Tx Ch #4 Speaker
Rx Ch #1 S-1 S-1 S-1 S-1 S-1
Rx Ch #2 S-2 S-2 S-2 S-2 S-2
Rx Ch #3 S-3 S-3 S-3 S-3 S-3
Rx Ch #4 S-4 S-4 S-4 S-4 S-4
-
-
Mic Input S-5 S-5 S-5 S-5 S-5
Sum Audio In S-6 S-6 S-6 S-6 S-6
Table 3. Parallel Transmit Line Resistor Network Selection
Tx Ch # Resistor Designation Parallel Lines, Resistor Value / Line Loss (dB)
234
1 R112, R113 300 Ω/6dB 620 Ω / 9.5 dΒ 910 Ω / 12.0 dΒ
2 R119, R121 300 Ω/6dB 620 Ω / 9.5 dΒ 910 Ω / 12.0 dΒ
3 R109, R110 300 Ω/6dB 620 Ω / 9.5 dΒ 910 Ω / 12.0 dΒ
4 R118, R120 300 Ω/6dB 620 Ω / 9.5 dΒ 910 Ω / 12.0 dΒ
4
4.4 Securing the Connections
After all power and line connections are made,
the wires should be neatly bundled and secured
in place to prevent accidental breakage when in
service. Use one or more of the cable guides
supplied with the card rack, or tie in place with
appropriate wire ties.
4.5 Interface connector Numbering
The Tellabs (or equivalent) card cage interface
connector pins may have a different numbering
scheme than the 1505. Table 4 depicts the card
edge pin numbers as shown in the schematic,
which is also the same as one type of connec
tor, followed by two alternate numbering
schemes as used on other connectors. Dili
gently review the actual connections being
used, to Table 4, to ensure proper connections
are made for optimum performance. Record the
external connections made during installation in
the blanks rows in Table 4’s “User Connection” column (make copies of Table 4 and keep
records for each 1505).
5. Operation
5.1 Description
This 1505 module has up to four, receive balanced 600 Ω line inputs or high impedance un-
balanced inputs, along with a Mic/Handset input, that is user configurable by dip switch set-
ting, to drive from one to four 600 Ω balanced
transmit line outputs, or an 8 Ω remote speaker.
The module is also capable of summing up to
four receive channel inputs and/or a Mic/Hand
set input, into one or more transmit line outputs
or the speaker output.
5.2 Operating Capabilities
The 1505 accepts up to four balanced or unbal
anced inputs, switch selectable by the user, to
four balanced line driver outputs. These inputs
are also externally mutable by switched low in
puts at the rear panel connection. In addition,
the module will accept a microphone or hand
set input through the front panel jack or the
rear panel connector.
The transmit amplifier is a 600-ohm balanced
line output. The module has four balanced line
outputs. Each amplifier output is adjustable
-
-
with a range of -15 to 10 dBm.
The module has a speaker amplifier output that
may drive an eight ohm external speaker with
an output level of 1 watt. The level is adjust
able.
Any line or microphone input may be switched
(through a module dip switch) to any line output or the speaker output. Three 1505s can be
connected so one line input may drive up to
twelve 600-ohm line outputs. Each input is mutable and the control is a switched low on the
rear panel connector. A PTT from the microphone or handset will gate on the microphone
amplifier and is also jumper selectable to mute
the speaker to inhibit crosstalk.
5.3 Controls and Indicators
Front panel LEDs light when the corresponding
-
receive channel or speaker is muted and when
the microphone or handset PTT switch is acti
vated.
A compressor/limiter circuit is available by
jumper selection for each receive circuit, to
limit the input level to a predetermined setting,
which assists in maintaining proper system lev
els. This module also contains a summed input
circuit, and a summed output circuit, to allow it
to be used in a matrix, i.e. three modules can
be configured to allow a single input to drive
twelve outputs, or conversely twelve inputs can
be summed to one output.
Active switch input circuits allow for muting
individual receive input channels, or the
speaker. A PTT input activates the microphone
circuit.
-
5
Loading...