Here’s a concise, practical rundown of the “top” aircraft communication systems — organized by function, with what they do, typical platforms, and short pros/cons or notes.

1. Voice radios

• VHF COM (very-high-frequency voice radio)
  • Purpose: Primary short/medium‑range ATC voice (line‑of‑sight, ~200 NM depending on altitude).
  • Platforms: All commercial, business, GA.
  • Notes: Standard for terminal and en‑route ATC; modern avionics support 8.33 kHz channel spacing where required.
• HF COM (high-frequency)
  • Purpose: Long‑range voice over oceans/remote areas (skywave propagation).
  • Platforms: Long‑range airliners, business jets on oceanic routes.
  • Notes: Lower voice quality/latency; often supplemented/replaced by satcom for many operators.
• SELCAL (selective calling)
  • Purpose: Alerts crew when ground station is calling on HF/voice channels (used in oceanic ops).

2. Satellite communications (SATCOM)

• L-band (e.g., Inmarsat SwiftBroadband)
  • Purpose: Global voice and moderate-speed data (safety voice, ACARS, email).
  • Platform: Airliners, business jets.
  • Strengths: Wide coverage, mature safety services.
• Iridium (Iridium Classic, Iridium Certus)
  • Purpose: Truly global voice/data via low‑Earth orbit (including polar coverage).
  • Platform: Business jets, remote ops, some airliners.
  • Strengths: Global/polar coverage, improving data speeds (Certus).
• Ka-/Ku‑band aero systems (high‑throughput for inflight Wi‑Fi)
  • Purpose: High‑bandwidth passenger internet and large data transfers.
  • Providers: Panasonic, Viasat, Gogo (historically), Thales, etc.
  • Strengths: High throughput; lower latency for Ka than older L‑band.
• Use case: SATCOM replaces or augments HF for long‑range voice/data and enables modern connectivity and datalinks.

3. Datalink systems (air‑ground data)

• ACARS (Aircraft Communications Addressing and Reporting System)
  • Purpose: Digital messaging for operational messages, maintenance, position reports.
  • Transport: VHF, HF, SATCOM, VDL depending on region.
• VDL Mode 2 / VDL Mode 3
  • Purpose: VHF datalink used to carry ACARS and other messages; higher capacity than legacy ACARS on simple VHF.
• CPDLC (Controller–Pilot Datalink Communications)
  • Purpose: Text-based clearances and messages with ATC (reduces voice load, used in oceanic and busy flows).
  • Platforms: Airliners and long‑range business jets (where ATS supports it).
• FANS / ATN
  • Purpose: Standards (e.g., FANS-1/A, ATN Baseline) enabling datalink in oceanic/remote airspace.

4. Surveillance / transponders / collision avoidance

• Transponders (Mode A/C, Mode S)
  • Purpose: ATC altitude/ID reporting; Mode S supports selective interrogation and data exchange.
• ADS‑B Out (Automatic Dependent Surveillance–Broadcast)
  • Purpose: Real‑time broadcast of position/velocity for ATC/traffic; increasingly required.
• ADS‑B In
  • Purpose: Receives traffic/weather broadcasts (enhances situational awareness).
• TCAS / ACAS (Traffic Collision Avoidance System)
  • Purpose: Cooperative traffic detection and resolution advisories (not passive comms with ATC but exchanges transponder interrogation).

5. Onboard/operator/crew comms and emergency

• Interphone / Audio Control Panels and PA systems
  • Purpose: Cockpit and cabin announcements, crew coordination.
• ELT (Emergency Locator Transmitter)
  • Purpose: Emergency position beacon for SAR.
• Satphones and portable satcom units
  • Purpose: Crew or passenger voice/data when installed or carried.

6. Integrated avionics / communications suites (manufacturers)

• Major avionics/comm integrators: Honeywell, Collins Aerospace (Rockwell Collins), Thales, Garmin, L3Harris, Avidyne.
• Inflight connectivity/internet providers: Panasonic Avionics, Viasat, Gogo (and others).
• Note: These suppliers package radios, SATCOM, ACARS/VDL, transponders, and connectivity into certified integrated solutions.

Quick comparisons / guidance

• For short/terminal ops: VHF COM + Mode S transponder + ADS‑B Out (+ ADS‑B In if desired) is essential.
• For oceanic/long‑range: Add HF and/or SATCOM, SELCAL, CPDLC (where required), ACARS via satellite or HF.
• For high throughput (airline passenger Wi‑Fi or big data needs): Ka/Ku‑band SATCOM or hybrid LEO/MEO solutions; higher cost and weight.
• For global polar ops: Iridium (LEO) provides true global/polar coverage; Inmarsat historically has strong mid‑latitude coverage.
• For small GA: VHF COM, transponder/ADS‑B Out, ELT; add portable satcom or Iridium for remote operations.

If you want, I can:

• Recommend specific systems or vendors tailored to a particular aircraft type or mission profile (airliner, regional, business jet, GA).
• Compare two or three specific systems (e.g., Iridium Certus vs Inmarsat SwiftBroadband vs Ka‑band) in more detail.