🛡 Field Communications Code Reference
Logistics 4×4 · Edition 1 · 2026 · Chameleon AI Agent Ltd
A compact code protocol for use when data connectivity is unavailable. Designed for truck drivers, hikers, and emergency services operating across borders or in remote terrain. Three user profiles share a common alert and system vocabulary — enabling cross-agency communication even under severely degraded conditions.
Sharing this reference is encouraged. Interoperability depends on all parties knowing the codes.
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⬇ Download PDF backup ← Back to Logistics 4×4How the codes work
Each code is a letter (category) followed by two digits (severity or sub-type). Within each category, lower numbers mean normal or minor, higher numbers mean serious or critical. The 99 code is always the most severe.
A 1 1
│
└─┴── Severity 11 = nominal → 99 = emergency
└────── Category letter
Multiple codes can be combined in a single message. A free-text note can be appended for additional detail.
D
Driver
Truck / cross-border operator
H
Hiker
Outdoor / trekking team member
X
Emergency Services
SAR / paramedic / ranger / fire
Universal SOS — works on all profiles
Send these two codes together to trigger an immediate life-threat emergency alert with GPS location to all registered contacts.
A99
H99
Universal codes — all profiles
A (Alert) and Z (System) are identical across Driver, Hiker, and Emergency Services
A
Alert level
| Code | Meaning |
|---|---|
| A11 | All clear. Situation normal. |
| A22 | Minor incident. Self-handling. |
| A33 | Caution. Possible problem developing. Monitoring. |
| A44 | Assistance needed. Non-urgent. |
| A55 | Assistance needed urgently. |
| A66 | Serious incident in progress. |
| A77 | Critical situation. Multiple problems. |
| A88 | Extreme danger. |
| A99 | SOS. Life threatening emergency. Send help immediately. |
Z
System / protocol
| Code | Meaning |
|---|---|
| Z00 | Heartbeat. No change. |
| Z01 | Start of shift / hike / deployment. |
| Z02 | End of shift / hike. Safely stood down. |
| Z03 | Message acknowledged. |
| Z04 | Message corrupted. Please resend. |
| Z05 | Relay this message forward. |
| Z06 | Relay this message back to base. |
| Z07 | Base or command requesting status from all. |
| Z08 | Requesting status from this specific contact. |
| Z09 | Group or convoy disbanding. |
Driver codes — prefix D
Truck operators, cross-border logistics, convoy drivers
B
Border
| Code | Meaning |
|---|---|
| B11 | Approaching border. Within twenty kilometres. |
| B22 | In queue at border post. Normal wait. |
| B33 | Delayed at border. Paperwork issue. |
| B44 | Goods inspection ordered. |
| B55 | Unofficial payment demanded. |
| B66 | Goods seized by authorities. |
| B77 | Vehicle impounded. |
| B88 | Driver detained. |
| B99 | Refused entry. Turned back. |
C
Cargo
| Code | Meaning |
|---|---|
| C11 | Cargo loaded. All secure. Normal. |
| C22 | Partial load or minor shift. |
| C33 | Load shifted. Stopping to re-secure. |
| C44 | Cargo damaged. |
| C55 | Spillage or items fallen from vehicle. |
| C66 | Cargo partially stolen. |
| C77 | All cargo stolen or seized. |
| C88 | Hazmat or cold-chain incident. |
| C99 | Total cargo loss. |
D
Driver status
| Code | Meaning |
|---|---|
| D11 | Driver on duty. Driving normally. |
| D22 | Driver on a stop. Fuel, meal, or break. |
| D33 | Driver loading or unloading cargo. |
| D44 | Driver waiting. Customs, checkpoint, or traffic. |
| D55 | Driver delayed. Problem. Cannot proceed yet. |
| D66 | Driver feeling unwell or fatigued. |
| D77 | Driver detained or facing legal issue. |
| D88 | Driver breakdown. Cannot continue without help. |
| D99 | Driver emergency. Driver in danger. |
E
Vehicle fault
| Code | Meaning |
|---|---|
| E11 | Engine warning light. Minor. Continuing. |
| E22 | Single flat tyre. Changing now. |
| E33 | Multiple flat tyres. Cannot change. |
| E44 | Engine overheating. Pulled over. |
| E55 | Mechanical breakdown. Non-engine. |
| E66 | Complete engine failure. |
| E77 | Fire. |
| E88 | Accident damage. Vehicle cannot move. |
| E99 | Vehicle write-off. Total loss. |
F
Fuel
| Code | Meaning |
|---|---|
| F11 | Fuel tank full. |
| F22 | Fuel three-quarter. |
| F33 | Fuel half. |
| F44 | Fuel quarter. |
| F55 | Fuel low. Need refuel within 50 km. |
| F66 | Fuel critical. Need refuel now. |
| F77 | Running on jerry cans or reserve tank. |
| F88 | Fuel contaminated or wrong fuel used. |
| F99 | No fuel. Stopped. |
G
Convoy
| Code | Meaning |
|---|---|
| G11 | Solo vehicle. No convoy. |
| G22 | Convoy lead vehicle. |
| G33 | Convoy mid position. |
| G44 | Convoy tail vehicle. |
| G55 | Convoy intact. All trucks present. |
| G66 | One vehicle missing from convoy. |
| G77 | Multiple vehicles missing. |
| G88 | Convoy separated. Regroup at next waypoint. |
| G99 | Convoy disbanded. |
H
Help needed
| Code | Meaning |
|---|---|
| H11 | Need fuel delivered to my location. |
| H22 | Need mechanic or mobile workshop. |
| H33 | Need medical assistance or ambulance. |
| H44 | Need police or official escort. |
| H55 | Need recovery truck or crane. |
| H66 | Need food, water, or supplies. |
| H77 | Need customs agent or documentation help. |
| H88 | Need armed escort. |
| H99 | Major incident. All assistance needed urgently. |
J
Journey progress
| Code | Meaning |
|---|---|
| J11 | Journey started. Departed on schedule. |
| J22 | 25% of route complete. |
| J33 | Halfway. 50% complete. |
| J44 | 75% complete. |
| J55 | Approaching destination. Under 10 km. |
| J66 | Arrived at destination. |
| J77 | Route significantly extended. Major detour. |
| J88 | Turned back. Retracing route. |
| J99 | Lost. Off route entirely. |
K
Communications
| Code | Meaning |
|---|---|
| K11 | Full communications. All normal. |
| K22 | Data only. No voice calls. |
| K33 | SMS only. No data or voice. |
| K44 | Voice only. No data or SMS. |
| K55 | Radio contact only. |
| K66 | Satellite communications active. |
| K77 | Mesh WiFi only. No cellular. |
| K88 | This message relayed via another device. |
| K99 | No communications. Sent via third party. |
R
Road conditions
| Code | Meaning |
|---|---|
| R11 | Good tarmac road. |
| R22 | Tarmac with potholes. |
| R33 | Gravel or dirt road. Passable. |
| R44 | Rough track. Mud or poor surface. |
| R55 | Road partially blocked. |
| R66 | Road closed or one-lane obstruction. |
| R77 | Bridge out or dangerous. |
| R88 | Road impassable. |
| R99 | No route. Off road or completely lost. |
S
Security
| Code | Meaning |
|---|---|
| S11 | Situation normal. No threats. |
| S22 | General caution in area. |
| S33 | Unofficial checkpoint or vehicle following. |
| S44 | Criminal roadblock reported ahead. |
| S55 | Bribe demanded. |
| S66 | Robbery attempt. Repelled. |
| S77 | Robbery in progress. |
| S88 | Armed attack on convoy. |
| S99 | Hijack or kidnap. |
T
Schedule
| Code | Meaning |
|---|---|
| T11 | On time. On schedule. |
| T22 | Slightly delayed. Under one hour. |
| T33 | Delayed one to two hours. |
| T44 | Delayed two to four hours. |
| T55 | Delayed four to eight hours. |
| T66 | Delayed one day. |
| T77 | Major delay. ETA unknown. |
| T88 | Schedule abandoned. |
| T99 | Trip aborted. Returning. |
V
Vehicle movement
| Code | Meaning |
|---|---|
| V11 | Vehicle parked. Stopped safely. |
| V22 | Vehicle moving normally. |
| V33 | Vehicle moving slowly. Under 20 km/h. |
| V44 | Vehicle stuck. Mud, sand, or ditch. |
| V55 | Towing another vehicle. |
| V66 | Being towed. |
| V77 | Vehicle overturned. |
| V88 | Accident. Vehicle cannot move. |
| V99 | Write-off. Total loss. |
W
Weather
| Code | Meaning |
|---|---|
| W11 | Clear and dry. Good visibility. |
| W22 | Light rain or haze. |
| W33 | Heavy rain. |
| W44 | Thunderstorm or high wind. |
| W55 | Fog or poor visibility. |
| W66 | Flood. Road wet but passable. |
| W77 | Flood. Road impassable. |
| W88 | Dust storm or harmattan. Near zero visibility. |
| W99 | Extreme weather conditions. Stopped. |
Hiker codes — prefix H
Trekkers, outdoor teams, wilderness expeditions
H
Help needed
| Code | Meaning |
|---|---|
| H11 | Need food or water. |
| H22 | Need first aid or medical kit. |
| H33 | Need medical assistance or evacuation assessment. |
| H44 | Need rescue team. |
| H55 | Need helicopter or air evacuation. |
| H66 | Need search and rescue. |
| H77 | Need shelter or emergency bivouac. |
| H88 | Need urgent evacuation. Cannot walk. |
| H99 | Major emergency. All assistance needed immediately. |
T
Trail conditions
| Code | Meaning |
|---|---|
| T11 | Good trail. Well marked. Easy going. |
| T22 | Trail intermittent or overgrown. |
| T33 | Trail lost. Navigating by GPS or compass. |
| T44 | Off trail. Open terrain. Navigable. |
| T55 | Steep ascent. Slowing pace. |
| T66 | Steep descent. Taking care. |
| T77 | Technical terrain. Scramble, rock, or snow. |
| T88 | Dangerous section. Crossing carefully. |
| T99 | Terrain impassable. Forced to turn back. |
U
Gear / equipment
| Code | Meaning |
|---|---|
| U11 | All gear in good condition. |
| U22 | Minor gear issue. Non-critical. |
| U33 | Gear damaged but workaround found. |
| U44 | Critical item failing. Tent, stove, or filter. |
| U55 | Navigation equipment lost or failed. |
| U66 | First aid kit in use. |
| U77 | Emergency shelter needed. Setting up bivouac. |
| U88 | Multiple critical gear failures. |
| U99 | All essential gear lost. Catastrophic. |
V
Vitals / group health
| Code | Meaning |
|---|---|
| V11 | All group members fit and well. |
| V22 | Minor fatigue or discomfort. Continuing. |
| V33 | Blisters or minor injury. Slowing slightly. |
| V44 | Injury. Significantly slower pace. |
| V55 | Member cannot maintain normal pace. |
| V66 | Serious injury. Stopped. Assessing evacuation. |
| V77 | Member collapsed or unconscious. |
| V88 | Medical emergency. Evacuation required. |
| V99 | Life threatening. Emergency services needed immediately. |
Y
Scheduled check-in
| Code | Meaning |
|---|---|
| Y11 | Scheduled check-in. All well. On route. |
| Y22 | Check-in. Slight delay. Still safe. |
| Y33 | Check-in. Significant delay. Still safe. |
| Y44 | Off route but safe and navigating. |
| Y55 | Missed previous check-in window. Now reporting. |
| Y66 | Requesting acknowledgement from base. |
| Y77 | Safe arrival at camp or planned waypoint. |
| Y88 | Descending. Final leg to trailhead. |
| Y99 | Multiple check-ins missed. Emergency alert triggered. |
S
Security
| Code | Meaning |
|---|---|
| S11 | Situation normal. No threats. |
| S22 | General caution. Unfamiliar area. |
| S33 | Suspicious activity nearby. |
| S44 | Wildlife threat. Keeping distance. |
| S55 | Wildlife encounter. Backing away. |
| S66 | Aggressive wildlife. Retreating. |
| S77 | Hostile people encountered. |
| S88 | Threatened or followed. Moving to safety. |
| S99 | Immediate danger from people or wildlife. |
Emergency Services codes — prefix X
SAR, paramedics, fire crews, rangers — degraded-comms operations
Aligned with international emergency standards
The P (triage) category uses the international P1–P4 priority scale (P1=Immediate, P2=Delayed, P3=Minor, P4=Expectant). The I (incident) and N (count) categories reflect the METHANE major-incident declaration framework used by joint emergency services.
I
Incident type
| Code | Meaning |
|---|---|
| I11 | Medical emergency. No scene hazard. |
| I22 | Road traffic collision. |
| I33 | Search and rescue. Missing person. |
| I44 | Fire or structural incident. |
| I55 | Flood or water rescue. |
| I66 | Hazardous materials or chemical release. |
| I77 | Structural collapse. |
| I88 | Civil unrest, violence, or armed incident. |
| I99 | Major incident declared. |
P
Patient triage
| Code | Meaning |
|---|---|
| P11 | No casualties on scene. |
| P22 | Walking wounded only. P3 — minor. |
| P33 | Serious but stable. P2 — delayed. |
| P44 | Life-threatening casualties. P1 — immediate. |
| P55 | Expectant casualties. P4 — palliative. |
| P66 | Mixed triage. Multiple categories present. |
| P77 | Mass casualty incident declared. |
| P88 | Casualty count incomplete. Scene not cleared. |
| P99 | Catastrophic. Multiple fatalities confirmed. |
N
Number of casualties
| Code | Meaning |
|---|---|
| N11 | One casualty. |
| N22 | Two to five casualties. |
| N33 | Six to ten casualties. |
| N44 | Eleven to twenty casualties. |
| N55 | Twenty to fifty casualties. |
| N66 | Fifty to one hundred casualties. |
| N77 | Over one hundred casualties. |
| N88 | Unknown number. Scene assessment ongoing. |
| N99 | Casualties at multiple locations. |
V
Patient vitals
| Code | Meaning |
|---|---|
| V11 | Conscious and alert. Talking normally. |
| V22 | Conscious but confused or agitated. |
| V33 | Responding to voice commands only. |
| V44 | Responding to pain only. Unconscious. |
| V55 | Unresponsive. Breathing present. |
| V66 | Not breathing. CPR in progress. |
| V77 | Severe haemorrhage. Tourniquet applied. |
| V88 | Cardiac arrest. |
| V99 | Deceased. Confirmed. |
R
Resources on scene
| Code | Meaning |
|---|---|
| R11 | First aider only. No professional responder. |
| R22 | Paramedic or advanced first aider on scene. |
| R33 | Ambulance crew on scene. |
| R44 | Fire crew on scene. |
| R55 | Police on scene. |
| R66 | Multiple emergency services on scene. |
| R77 | Incident commander established. |
| R88 | Field hospital or casualty clearing station active. |
| R99 | All resources overwhelmed. Urgent reinforcement required. |
H
Resources required
| Code | Meaning |
|---|---|
| H11 | No additional resources required. |
| H22 | Additional ground ambulance required. |
| H33 | Air ambulance or helicopter required. |
| H44 | Fire and rescue required. |
| H55 | Police or armed response required. |
| H66 | HAZMAT or contamination team required. |
| H77 | Heavy rescue or urban search team required. |
| H88 | Military or specialist support required. |
| H99 | Mass casualty response. All resources required. |
E
Evacuation status
| Code | Meaning |
|---|---|
| E11 | No evacuation required. Treating on scene. |
| E22 | Self-evacuation possible. Casualties walking to transport. |
| E33 | Vehicle evacuation possible. Road is accessible. |
| E44 | Stretcher evacuation required. |
| E55 | Air evacuation required. Landing zone needed. |
| E66 | Water or boat evacuation required. |
| E77 | Technical rescue required. Rope or confined space. |
| E88 | Evacuation route compromised. Seeking alternative. |
| E99 | Evacuation impossible. Casualties sheltering in place. |
S
Scene safety
| Code | Meaning |
|---|---|
| S11 | Scene safe. No hazards. |
| S22 | Potential hazards present. Caution advised. |
| S33 | Fire, chemical, or structural hazard on scene. |
| S44 | Active threat. Scene not yet secure. |
| S55 | Hostile persons on scene. Law enforcement required. |
| S66 | Contamination hazard. Exclusion zone required. |
| S77 | Scene partially cleared. Ongoing risk. |
| S88 | Scene unsafe. Responders withdrawn. |
| S99 | Immediate danger to responders. Evacuate scene now. |
Quick reference — common situations
Same-meaning codes across the three profiles
| Situation | Driver (D) | Hiker (H) | Emergency (X) |
|---|---|---|---|
| All clear / normal | A11 | A11 | A11 |
| Need urgent help | A55 + H44 | A55 + H44 | A55 + H33 |
| Life threat — SOS | A99 + H99 | A99 + H99 | A99 + H99 |
| SMS-only comms | K33 | K33 | K33 |
| On schedule / en route | T11 / D11 | Y11 | J11 |
| Arrived at destination | J66 | J66 | J66 |
| Lost / off route | J99 | J99 | J99 |
| Severe weather | W77–W99 | W77–W99 | W77–W99 |
| Acknowledged | Z03 | Z03 | Z03 |
| Corrupted message | Z04 | Z04 | Z04 |
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© 2026 Chameleon AI Agent Ltd · Logistics 4×4 Field Communications Protocol · Edition 1
Sharing this reference is encouraged — interoperability requires it.