Product Overview
RTS' MRT-327 is a two-channel intercom station for use in RTS-TW intercom systems. It may be used as a headset station or as a speaker station (with an optional MCS-325 Modular Speaker). The MRT-327 may be installed in optional console or rack mount configurations.
Features:
- Call Signaling - The MRT-327 can send and receive 20 kHz call signals.
- Dual-Action Momentary/Latching Mic Switch - The Mic on/off switch can be used as a momentary push-to-talk switch or as a latching on/off switch.
- Remote Deactivation- The MRT-327 can receive 24 kHz “talk-off” signals for deactivation of the MRT-327 microphone from a remote location.
- Microphone Limiter - The microphone pre-amplifier circuit contains a limiter which helps to equalize output for different voice levels.
- Optional Microphone Speaker & Headset Configurations - The standard MRT-327 accepts an unbalanced, dynamic-mic headset or a dynamic microphone used in conjunction with an external speaker located on the rear panel. It also has a jack for an optional Model MCP-90-xx gooseneck panel microphone. Additionally, the MRT-327 may be internally modified for use with a carbon or balanced-dynamic microphone. It can also be modified to provide the microphone audio as an unswitched, balanced output.
- Powering Options - The MRT-327 receives operating power from the intercom line. It may be internally modified for local powering from a separate dc power supply or batteries.
Specifications:
- Input DC Voltage:
- Mode: 18 to 35 volts DC
- Local Power: 15 to 35 volts DC (12 to 15 volts DC, reduced performance)
- DC Current Drawn from TW Line:
- Quiescent: 45 mA ±10%
- Operating, 25 ohm phones: 75 mA ±10%
- Operating, 25 ohm phones + call light: 90 mA ±10%
- Operating, 8 ohm speaker: 240 mA ±10%
- Operating, 8 ohm speaker + call light: 300 mA ±10%
- Operating current is measured with output level at 10
- Local power option draws no current from TW line.
- DC Current Drawn from TW Line
- Notes: Operating current is measured with output level at 10 dB below clipping. Local power option draws no current from TW line.
- Impedance Across Line: 10,000 ohm, minimum (designed for use with 200O “TW” intercom lines)
- Environmental Temperature:
- Operating: 0°C to 60°C
- Storage: 40°C to 85°C
- Humidity: Operating and Storage: 5% to 95%, non-condensing
- Noise Contribution:
- (Ch 2): >-60 dBp
- (Ch 1): >-80 dBp
- Microphone Preamplifier:
- Input Impedance: 470 ohm ±5% (dynamic mic)
- Source Impedance: 200 ohm, nominal
- Maximum Input Level: 150 millivolts
- Frequency Response: (-54dB input): 100 Hz to 8 kHz ±3dB
- Limiter Range: 30 dB
- Carbon Mic Excitation Current: 10 mA, nominal
- Current Source:
- Transfer Ratio: 3.3 mA/volt = 3.3 millisiemens
- Output: 3.3 mA into 200 ohm = ±1 volt peak, nominal
- Speaker Amplifier:
- Maximum Voltage Gain: 30 dB
- Frequency Response: 100Hz to 8kHz ±4dB
- Output Power: 1.5 watts into 8 ohm nominal
- Speaker DIM (speaker muting during mic activation) adjustable, -4 to -30 dB (Factory set to -6 dB)
- Headphone Amplifier:
- Voltage Gain: 34 dB
- Output Voltage: 8 volts peak-to-peak into 25 ohm nominal
- Output power: 1/2 watt peak into 25 ohm
- Frequency Response: 150 Hz to 10 kHz ±3dB
- Headphone Impedance Range: 25 to 600 ohm (600 to 2000 ohm with reduced levels)
- Sidetone Adjustment Range: -20 dB to full on
- Call Light:
- Signalling Frequency: 20 kHz ±100 Hz
- Flashing Rate: 5 Hz ±2 Hz
- Talk-Off:
- Frequency: 24 kHz nominal
- Connectors:
- Dynamic Microphone Headset: XLR type 6-pin female
- Panel Microphone: 1/4" standard phone jack, 3-circuit
- Line Input: One (1) XLR type 3-pin female and one (1) XLR type 3-pin male, wired in parallel
- Mechanical:
- Dimensions: 1.71" (44 mm) tall, 8.2" (208 mm) wide, x 9.0" (228 mm) deep
- Weight: 2.75 lbs (1.25 kg)
- Construction/Finish: Aluminum case, thermoplastic front panel, light gray finish
