Telex 1505 User Manual
Page 4
4. 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 connec-
tions.
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) by-
passes Rx Ch #1’s Compressor/Limiter. Refer
to Table 1 and the schematic for the appropri-
ate jumper selection.
Table 1. Jumper Options
3
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.
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