Telex 1505 - Manual (Page 6)

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 Connec-
tion” 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 bal-
anced 600 Ω line inputs or high impedance un-
balanced inputs, along with a Mic/Handset in-
put, 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.
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.
5.2 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 out-
put 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 mu-
table and the control is a switched low on the
rear panel connector. A PTT from the micro-
phone 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.
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