Hi-Z Input; Test Microphone Input; External Tone Input; External Alc Input - RF Technology T220 Operation And Maintenance Manual

7 SPECIFICATIONS

7.4.15 HI-Z Input

7.4.15 HI-Z Input
Impedance - 10KΩ Nominal, balanced input
Input Level - 25mV to 1V RMS
7.4.16 Test Micr ophone Input
200Ω dynamic, with PTT
7.4.17 Exter nal Tone Input
Compatible with R220 tone output
7.4.18 Exter nal ALC Input
Output will be reduced 20dB by pulling the input down to below 1V. (Typically more
than 40dB attenuation is available.) The input impedance is ≅10kΩ, internally pulled
up to rail.
The external ALC input can be connected to the power control circuit in Eclipse
external power amplifiers.
7.4.19 T/R Relay Dr iver
An open collector transistor output is provided to operate an antenna change over relay
or solid state switch. The transistor can sink up to 250mA.

7.4.20 Channel Select Input/Output

Coding - 8 lines, BCD coded 00 - 99
Logic Input Levels - Low for <1.5V, High for >3.5V
Internal 10K pull down resistors select channel 00 when all inputs are O/C.

7.4.21 DC Remote Keying

An opto-coupler input is provided to enable dc loop keying over balanced lines or local
connections. The circuit can be connected to operate through the 600Ω line or through
a separate isolated pair.
RF Technology T220 Page 25