Operating instructions

RF Technology T350/T500 Page 7
2 TRANSMITTER INTERNAL JUMPER OPTIONS
1.1.8 TEST MIC
The TEST MIC. DIN socket is provided for use with a standard mobile or handset 200
Ohm dynamic microphone. The external audio inputs are disabled when the TEST
MIC’S PTT is on.
2 Transmitter Internal Jumper Options
In the following subsections an asterisk (*) signifies the standard (Ex-Factory)
configuration of a jumper.
2.1 JP2: EPROM Type
Condition Position
27C256 2-3 *
27C64 1-2
2.2 JP3: Dc Loop PTT
This jumper enables or disables the keying of the PTT function by means of a dc signal
passed down the 600Ω line input pair. When enabled, JP9-JP11 control how the dc
signal is configured with respect to an internal opto-coupler.
Condition Position
dc loop connected (enabled) 1-2 *
dc loop not connected (bypassed) 2-3
2.3 JP4: Audio Input Source
Either the 600Ω or the high-Z balanced inputs may be selected.
Condition Position
600Ω Input
2-3 *
High-impedance Input 1-2
2.4 JP5: 600 ? Termination
Normally the Line Input is terminated in 600?. The 600 ohm termination can be
removed by choosing the alternate position.
Condition Position
600? Termination 1-2*
No Termination 2-3