12
J3-7: PTT Output (Yellow):
This output from the system provides a ground (logic-low) when the system needs to
transmit over the radio. This output is an open-collector type which means that the output is an open circuit when
not transmitting. Connect this to the PTT input of the base station radio.
J3-8: Speaker – (Violet):
Connect to Speaker– of the base station radio. See below for more information.
J3-9: S or Single Ended Speaker High (Orange):
Audio received by the radio is fed into the system
using the S/- inputs of the system. These inputs to the system may be connected to the S/-
radio outputs. If the radio does not offer a speaker– output or if you wish to use a different RX audio output from
the radio other than speaker, connect that output to and leave Speaker– unconnected.
J3-10: LTR Delay (Gray):
This signal from the radio to the system is used by the system to know when a channel
is acquired on a trunking system like LTR. If the radio system is not a trunked system, the input may be left
unconnected.
If on a trunking system, connect this to a point in the base station radio that changes logic level when a channel is
acquired on the trunking system. Some radio manufacturers refer to this as the Clear to Send output. Also, the
Trunking Delay option must be checked in the MPS software when configuring the system in order to support
trunking.
The default polarity for this input to the system is active-high. This means that the system will consider the radio
channel to have been acquired when the logic level is high. The polarity may be changed to active-low by moving
jumper JP20 from the 1-2 position to the 2-3 position.
SPEAKER-MICROPHONE J4
Connect the optional administrator speaker-microphone to this connector.
TELEPHONE LINE J6
If the system has the optional telephone interface installed, connect to system to the telephone line via this
connector. Be careful to connect the telephone line only to J6 and not to one of the other larger connectors or
damage may result.
PA EQUIPMENT J7
J7-1: E Lead (Brown):
Not used. Leave unconnected.
J7-2: Ground (Blue):
Connect to a grounding point on the PA equipment.
J7-3: PTT OC (White):
Not used. Leave unconnected.
J7-4: PA TX Out A (Black):
This is one side of the balanced audio output from the system to the PA microphone
input. Connect this to one side of the balanced microphone input of the PA equipment.
J7-5: Unbalanced Out (Red):
This is an unbalanced audio output from the system to the PA equipment which
may be used if a balanced input is not available. The default output impedance is 1 K Ohm. If needed, remove
jumper JP9 to change output impedance to 47 K Ohm.
J7-6: Ground (Green):
This supplemental ground connection is provided for use with the unbalanced audio
output if needed.
J7-7: PA TX Out B (Yellow):
This is one side of the balanced audio output from the system to the PA
microphone input. Connect this to one side of the balanced microphone input of the PA equipment.
J7-8: All Call (Violet):
This may be connected to the all call input of the PA equipment if needed. It is the
normally open (NO) contact of the form C relay that is energized when the system broadcasts over the PA.
