Communications Modes Table Mode of Communication How it Reliability Availability Advantages Limitations Runners Volunteers carry messages from one location to another Extremely reliable Any reliable person can be used as a runner Reliability Flexibility Familiar with environment Availability No special training Distance and time Requires written information for accuracy Availability Requires familiarity with the area Landline Telephones Phones that are powered by themselves and rely on local telephone lines May operate during power failures, but handheld batteries can die and digital phones may or may not work Local telephone system generally fails when a large number of people in an area attempt to use phone at the same time Very common Familiarity Commonplace Enhanced 9-1-1 Data transfer Not mobile System overloads easily Network susceptible to physical damage May be affected by failure Cellular Phones Phones that transmit signals relayed by cell phone towers Vulnerable to the same weaknesses as telephones Cell towers require electricity to operate Very common Familiarity Mobility Commonplace Text messaging Towers may fail due to power outage or damage System overloads easily Local service (voice) generally fails when a large number of people in an area attempt to use service at the same time Requires less bandwidth – may get through when will not Camera phones Requires knowledge of numbers May be dependent on landlines
Satellite Phones Relays transmissions via satellite. If other phone systems are down, can only communicate locally with other satellite phones Rare Always on Global operation Expensive Rare Requires visibility to sky or building with compatible antenna Computer Communications Transmits data via the Internet or by runners USB drives or other media such as CDs May work when other systems are down Very common May work when systems down Provides electronic record Versatile network connections Relatively secure Large amounts of information information Thumb drives and discs do not require Internet Information redistribution Equipment may not be mobile May require Internet connectivity Requires specific hardware Expensive Requires source
repeaters and external antennas available at hobbyist stores specializing in communications 3-4 mile range for handhelds Increase range with repeaters and external antennas Transmit or data No license required Limited availability More expensive than FRS/GMRS radios Citizen Band (CB) Radios that transmit and receive on public frequencies Have 40 channels, but due to frequency they are practically useless for short range transmissions Common No license required 40 channels Casual conversation Not reliable Not recommended for CERT use Public Safety Bands A special communication mode used by emergency dispatchers, fire fighters, EMS, police, and other government emergency responders Extremely reliable Limited; must be used with jurisdictional protocol Direct communication to emergency first responders, if authorized Extremely reliable up to 20 miles with simplex, 50 miles with repeaters Handheld, mobile, or base units Requires authorization of jurisdiction Expensive Must be used with jurisdictional protocol Licensed to municipality or government entity
Amateur Radio Available in a variety of configurations; transmit repeaters and antennas Very reliable Widely available Various data types (voice, text, data, photos, documents, television) Range in excess of 100 miles with repeaters Operates simplex or repeaters Good availability Moderately priced Handheld, mobile, and base stations available Reliability Interoperability More simultaneous conversations possible Connect to computer Connect to global positioning system (GPS) and automated position reporting system (APRS) Requires license No business use Operators cannot be paid Complex radios Complex protocols Must work with existing area Emergency Communications Plans