The FM+ Intercom System is built for environments where audio must be dependable, visible, and easy to manage at scale. By combining FM broadcast with optional Wi-Fi streaming, it gives venues multiple ways to deliver clear audio without adding operational complexity.
This configuration includes 12 PPA R38 receivers paired with the FM T55 transmitter, making it well suited for facilities that need more receiver-level feedback than entry-level systems provide.
$4,285.00
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The FM+ Intercom System centers around the FM T55 transmitter, which broadcasts audio simultaneously over FM and Wi-Fi.
This allows venues to support both dedicated receivers and mobile-device listening without running separate systems. The transmitter includes multiple digital and analog input options and an OLED screen for fast configuration and monitoring.
What sets this package apart is the use of PPA R38 receivers. Each receiver includes a built-in OLED display that shows channel selection, battery status, and signal information. This makes the system easier to manage in environments where staff need quick visual confirmation that devices are functioning correctly.
With support for 17 wideband FM channels between 72 and 76 MHz, the system adapts well to busy RF environments while remaining compliant with ADA hearing assistance guidelines.
The FM+ Intercom System (FM 558-12) is designed for venues that need predictable performance, clear receiver feedback, and flexibility without moving into networked AV complexity.
Included in this system:
Performance highlights:
The FM+ Intercom System with 12 R38 receivers is a strong fit for venues that value control and visibility over simplicity alone, without requiring Dante or advanced network routing.
| SPECS | |
| Dimensions | 8.45″ W × 8.25″ D × 1.72″ H (21.5 cm × 21 cm × 4.4 cm) |
| Weight | Transmitter: 3.2 lbs (1.45 kg) |
| Color | Black/Silver with silver legends on the front, white legends on the back |
| Rack Mount | Standard 19″ rack, one EIA rack space high, ½ space wide. 1–2 units can be mounted in a single rack space with optional RPK 005 (single) or RPK 006 (double) rack mount kits. |
| Power Supply | Desktop Style Transformer (TFP 062); Input: 100–240 VAC, 50/60 Hz (IEC line cord); Output: 24 VDC, 750 mA, 18W; 2.5mm ID center positive barrel connector |
| Power ON Indicator | Push On/Push Off latching power button; backlit green indicates power ON; backlight off indicates power OFF; fading indicates Sleep Mode |
| Temperature Range | Operating: +32° F to +122° F (0° C to 50° C); Storage: -4° F to +158° F (-20° C to 70° C) |
| User Interface | 3.12″ High Resolution OLED display with selections via buttons. Hosted web page. Remote control and monitoring. |
| Dante | Only available on FM T55 D |
| Ethernet | RJ-45 supports CAT 5e up to 328 ft (100 m); 10/100 Base-T IEEE 802.3 compliant; unique MAC address |
| RF Section | |
| Operating Frequencies | 72.1–75.9 MHz, 17 wideband channels (selectable) |
| Frequency Accuracy | ±2 ppm stability, 0–50° C |
| Deviation | ±75 kHz maximum |
| Pre-Emphasis | 75 microsec |
| RF Field Strength | Does not exceed 80 mV/m at 3 m |
| Compatible Antennas | ANT 005, ANT 021, ANT 024, ANT 025 (refer to Williams AV’s Antenna Selection Install Guide for FCC-compliant antennas) |
| Transmission Range | Up to 1000 ft (304 m) with ANT 005 coaxial antenna mounted on rear chassis connector |
| RF Outputs | (1×) #10-32 stud connector in center of unit (pcb mounted); (1×) F-connector on rear chassis |
| RF Transmit Indicator | 1 Green LED On Air indicator |
| RF Power | Full, Medium, Low or OFF (indicated by menu icon) |
| RF Time Out (Sleep Mode) | 30 min duration, 4 hr duration, or Always On (menu selectable). Starts when audio is below -18 dB level with no button pressed for selected duration. |
| Audio Section | |
| Audio Processor Functions | DSP based; Compression: 1:1, 1.5:1 or 2:1; High-pass and Low-pass filter frequency control |
| Frequency Response | 31–16,000 Hz, ±3 dB (re: 1 kHz, ±3 dB) (“Music” Audio Preset) |
| Signal-to-Noise Ratio | 67 dB (typical) transmitted RF |
| Total Harmonic Distortion | Less than 0.25% @ 1 kHz (RF output) |
| Common Mode Rejection | Greater than 57 dB @ 1 kHz, Mic or Line |
| Audio Inputs | (1×) Combination 3-pin XLR / ¼″ (TRS) jack for balanced or unbalanced line level, or balanced/unbalanced microphone with selectable phantom power |
| Audio Input Gain Adjust | Menu adjustable 0 to -50 dB in 1 dB steps |
| Phantom Power | 14.4 VDC applied through 2.2 kΩ resistors to analog combo jack (XLR Pins 2 & 3 / TRS tip & ring) |
| Audio Level Indicators | 10-LED array reading -18 to +9 dB at 3 dB intervals: 7 green, 2 amber, 1 red |
| Headphone Output | ¼″ TRS stereo jack, mono signal; 14.85 mW at +9 dB max into 33 Ω (level adjustable 0 to -40 dB in 2 dB steps) |
| Line Output | RCA jack (black), -10 dBV (.32 VRMS); output impedance 100 ohms at +9 dB |
| Input Levels (Bal/Unbal) – Microphone (Gain = 0 dB) | Nominal: -55 dBV (1.7 mV RMS) | Overload Warning: -22 dBV (80 mV RMS) | Absolute Max Rating: +20 dBV (10.0 V RMS) |
| Input Levels (Bal/Unbal) – Line (Gain = 0 dB) | Nominal: -25 dBV (55 mV RMS) | Overload Warning: +16 dBV (6.3 V RMS) | Absolute Max Rating: +20 dBV (10.0 V RMS) |
| Approvals | FCC, RoHS3, WEEE, Industry Canada |
| Warranty | 2-year parts and labor |
| Note | Specifications are subject to change without notice. Stresses above these ratings may cause permanent damage or degrade reliability. |
| EAR 022 | |
| Style | Around-ear speaker |
| Plug | 3.5 mm mono |
| Cord | 39″ |
| Driver Size | 23 mm |
| Nominal Impedance | 32 Ω |
| Freq. Response | 20 – 20 kHz |
| Weight | 15 g |
| Max Power Input | 30 mW |
| Sensitivity | 118 dB @ 1 kHz |
| IDP 008 | |
| Dimensions | 10-3/8″ (L) × 6-1/4″ (W) × 1/8″ (H) |
| NKL 001 | |
| Color | Black |
| Weight | 1.5 oz |
| Length | 18.5″ cord |
| Connector | NKL 001: 3.5 mm mono plug | NKL 001-S: 3.5 mm stereo plug with ring disconnected |
| Impedance | 8–16 Ohms |
| Input Power | 500 mW max |
| Magnetic Field Strength | 25 mW input at 1000 Hz produces 1.7 A/m at 6″ above the center of loop; 85 μW input produces 0.1 A/m (IEC Standard) |
| Approvals | RoHS, WEEE |
| Warranty | One Year |
| PPA R38N | |
| Dimensions | 4.1″ × 2.85″ × 1.38″ (104 × 72 × 35 mm) |
| Weight | 4.6 oz (130 g) with batteries; 2.6 oz (73 g) without batteries |
| Color | Black/Silver. Black ABS plastic case with aluminum faceplate. |
| Battery Type | (2) AA Alkaline or (2) AA NiMH rechargeable |
| Battery Life | (2) AA non-rechargeable alkaline (BAT 001-2): approx. 50 hrs; (2) AA rechargeable NiMH (BAT 026-2, 1500 mAh): approx. 32 hrs |
| Current Consumption | 52 mA nominal |
| Operating Temp. Range | 32° – 122°F (0° to 50°C) |
| Channels | 17 wideband, accessed via menu |
| Operating Frequencies | 72.1, 72.2, 72.3, 72.4, 72.5, 72.6, 72.7, 72.8, 72.9, 74.7, 75.3, 75.4, 75.5, 75.6, 75.7, 75.8, 75.9 MHz* |
| FM Deviation | 75 kHz |
| De-Emphasis | 75 µS |
| Display Screen | 1″ OLED |
| Power Indication | Power button, backlit green. Good battery strength: glows solid. Low battery: flashes. |
| Sensitivity | 2 µV at 12 dB Sinad with squelch defeated |
| Input Overload | 100 mV |
| Frequency Response | 200 Hz – 15 kHz, ±3 dB |
| Modulation | FM, ±75 kHz peak deviation |
| Signal-to-Noise Ratio | Minimum 65 dB @ 1.0V |
| Receive Antenna | Integral with earphone/headphone cord |
| Audio Output | 35 mW max at 16 Ω |
| Headphone Connector | 3.5 mm stereo jack, mono output for stereo or mono earphones/headphones |
| Supplied Earphone | Stereo earbud-type with foam cushion, 3.5 mm plug, 32 Ω |
| Power Save Mode | Enters sleep mode after approximately 3 minutes of no RF signal |
| Approvals | FCC, Industry Canada, RoHS, WEEE |
| Warranty | Lifetime PLUS Limited Warranty, 90 Days on most accessories |
| Warranty | |
| Warranty | 2 Years |
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R38 receivers are better when staff need visibility into device status. The OLED screen lets teams quickly check battery level, channel, and signal without guessing, which reduces troubleshooting during live use.
Yes. While the system offers more visibility than entry-level options, daily use is straightforward. Receivers power on ready to use, and channel changes are handled directly on-screen without technical setup.
Not significantly. The display is optimized for low power use and only activates when needed. Battery life remains suitable for full-day events when using standard alkaline batteries.
Yes. Because it uses FM broadcast, audio is not tied to fixed rooms or zones. Venues can reconfigure seating or spaces without rewiring or reprogramming the system.
The system offers 17 wideband FM channels between 72–76 MHz. This allows installers to select clean frequencies and avoid interference from nearby assistive listening or wireless audio systems.
Absolutely. Many venues use this system for seasonal events or rotating programs. Components are self-contained, require no calibration after setup, and can be redeployed quickly when needed. You can also opt for renting instead of buying, so it all depends on your needs.
Not necessarily. Smaller venues often choose R38 receivers specifically for the screen-based feedback, which helps staff confirm correct operation without audio testing or technical checks.
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