Those are Medical Dispatch Priority Codes. The first number is the type of medical call, the letter ranges from A (Alpha) which is a low level call, to an E (Echo) which is life threatening.
1A1 – Abdominal pain
1C1 – Fainting/near fainting
1C2 – Females fainting/near fainting
1C3 – Males pain above navel
1C4 – Females pain above navel
1D1 – Not alert
2A1 – No difficulty breathing/swallowing
2A2 – Spider bite
2B1 – Unknown status (3rd party caller)
2C1 – Difficulty breathing or swallowing
2C2 – Special medications or injections used
2D1 – Severe respiratory distress
2D2 – not alert
2D3 – Condition worsening
2D4 – Swarming attack (bee, wasp, hornet)
2D5 – Snakebite
2E1 – Ineffective breathing
4A1 – Not dangerous body area
3A2 – Non-recent injuries (=6 hours)
3A3 – Superficial bites
3B1 – Possibly dangerous body area
3B2 – Serous hemorrhage
3B3 – Unknown status (3rd party caller)
3D1 – Unconscious or arrest
3D2 – Not alert
3D3 – Dangerous body area
3D4 – Large animal
3D5 – Exotic animal
3D6 – Attack or multiple animals
4. Assault/Sexual Assault
4A1 – Not dangerous body area
4A2 – Non-recent injuries (=6 hours)
4B1 – Possibly dangerous body area
4B2 – Not alert
4B3 – Unknown status (3rd party caller)
4D1 – Unconscious or arrest
4D2 – Not alert
4D3 – Abnormal breathing
4D4 – Dangerous body area
4D5 – Multiple victims
5A1 – Non-traumatic back pain
5A2 – Non-recent traumatic back pain (=6 hours)
5C1 – Fainting or near fainting
5D1 – Not alert
6C1 – Abnormal breathing
6C2 – Cardiac history
6D1 – Severe respiratory distress
6D2 – Not alert
6D3 – Clammy
6E1 – Ineffective breathing
7A1 – Burns <18% body area
7A2 – Fire alarm (unknown situation)
7A3 – Sunburn or minor burns (= hand size)
7B1 – Unknown status (3rd party caller)
7C1 – Building fire with persons reported inside
7C2 – Difficulty breathing
7C3 – Burns =18% body area
7D1 – Unconscious or arrest
7D2 – Severe respiratory distress
7D3 – Not alert
7D4 – Explosion
7D5 – Multiple victims
8. Carbon Monoxide/Inhalation/Hazmat
8A1 – CO detector alarm (without priority symptoms)
8B1 – Alert without difficulty breathing
8C1 – Alert with difficulty breathing
8D1 – Unconscious or arrest
8D2 – Severe respiratory distress
8D3 – Hazmat
8D4 – Not alert
8D5 – Multiple victims
8D6 – Unknown status (3rd party caller)
9B1 – Obvious death (unquestionable)
9D1 – Ineffective breathing
9E1 – Suspected workable arrest – not breathing at all
9E2 – Suspected workable arrest – breathing uncertain (agonal)
9E3 – Suspected workable arrest – hanging
9E4 – Suspected workable arrest – strangulation
9E5 – Suspected workable arrest – suffocation
9E6 – Suspected workable arrest – underwater
9E7 – Expected death (EHSF change from EMD 9?1)
10A1 – Breathing normally <35
10C1 – Abnormal breathing
10C2 – Cardiac history
10C3 – Cocaine
10C4 – Breathing normally
10D1 – Severe respiratory distress
10D2 – Not alert
10D3 – Clammy
11A1 – Not choking now (can talk or cry, is alert and breathing normally)
11D1 – Not alert
11D2 – Abnormal breathing (partial obstruction)
11E1 – Choking
12. Convulsions/Seizures
12A1 – Not seizing now and breathing regularly (verified)
12B1 – Breathing regularly – not verified <35
12C1 – Pregnancy
12C2 – Diabetic
12C3 – Cardiac history
12D1 – Not breathing
12D2 – Continuous or multiple seizures
12D3 – Irregular breathing
12D4 – Breathing regularly – not verified
13A1 – Alert
13C1 – Not alert
13C2 – Abnormal behavior
13C3 – Abnormal breathing
13D1 – Unconscious
14A1 – Alert and breathing normally (no injuries and out of water)
14B1 – Alert and breathing normally (injuries or in water)
14B2 – Unknown status (3rd party caller)
14C1 – Alert with abnormal breathing
14D1 – Unconscious
14D2 – Not alert
14D3 – Diving or suspected neck injury
14D4 – Scuba accident
15C1 – Alert and breathing normally
15D1 – Unconscious
15D2 – Not disconnected from power
15D3 – Power not off or hazard present
15D4 – Long fall (=6 feet)
15D5 – Not alert
15D6 – Abnormal breathing
15D7 – Unknown status (3rd party caller)
15D8 – Not breathing/ineffective breathing
16. Eye Problems/Injuries
16A1 – Moderate eye injuries
16A2 – Minor eye injuries
16A3 – Medical eye problems
16B1 – Severe eye injuries
16D1 – Not alert
17A1 – Not dangerous body area
17A2 – Not recent (=6 hours) injuries (without priority medical symptoms)
17A3 – Public assist (no injuries and no priority symptoms)
17B1 – Possibly dangerous body area
17B2 – Serious hemorrhage
17B3 – Unknown status (3rd party caller)
17D1 – Dangerous body area
17D2 – Long fall (=6 feet)
17D3 – Not alert
17D4 – Abnormal breathing
18A1 – Breathing normally
18B1 – Unknown status
18C1 – Not alert
18C2 – Abnormal breathing
18C3 – Speech problems
18C4 – Sudden onset of severe pain (=3 hours)
18C5 – Numbness or paralysis
18C6 – Change in behavior (=3 hours)
19A1 – Heart rate =50 bpm and <130 bpm (without priority symptoms)
19A2 – Chest pain <35 (without priority symptoms)
19B1 – Unknown status (3rd party caller)
19C1 – Firing of AICD
19C2 – Abnormal breathing
19C3 – Chest pain =35
19C4 – Cardiac history
19C5 – Cocaine
19C6 – Heart rate <50 bpm or =130 bpm (without priority symptoms)
19D1 – Severe respiratory distress
19D2 – Not alert
19D3 – Clammy
20. Heat/Cold Exposure
20A1 – Alert
20B1 – Change in skin color
20B2 – Unknown status (3rd party caller)
20C1 – Cardiac history
20D1 – Not alert
21A1 – Not dangerous hemorrhage
21A2 – Minor hemorrhage
21B1 – Possibly dangerous hemorrhage
21B2 – Serious hemorrhage
21B3 – Bleeding disorder or blood thinners
21C1 – Hemorrhage through tubes
21D1 – Dangerous hemorrhage
21D2 – Not alert
21D3 – Abnormal breathing
22B1 – Unknown situation (not caught in machinery)
22D1 – Life status questionable
22D2 – Caught in machinery (unknown status)
22D3 – Multiple victims
23A1 – Poisoning (without priority symptoms) (EHSF change from 23?1)
23B1 – Overdose (without priority symptoms)
23C1 – Violent (police must rescue)
23C2 – Not alert
23C3 – Abnormal breathing
23C4 – Antidepressants (tricyclic)
23C5 – Cocaine (or derivative)
23C6 – Narcotics (heroin)
23C7 – Acid or alkali (lye)
23C8 – Unknown status (3rd party caller)
23C9 – Poison Control request for response
23D1 – Unconscious
23D2 – Severe respiratory distress
24. Pregnancy/Childbirth/Miscarriage
24A1 – 1st trimester hemorrhage or miscarriage
24B1 – Labor (delivery not imminent, =5 months/20 weeks)
24B2 – Unknown status (3rd party caller)
24C1 – 2nd trimester hemorrhage or miscarriage
24C2 – 1st trimester serious hemorrhage
24D1 – Breech or cord
24D2 – Head visible or out
24D3 – Imminent birth (=5 months/20 weeks)
24D4 – 3rd trimester hemorrhage
24D5 – High-risk complications
24D6 – Baby born
25A1 – Non-violent and non-suicidal (alert)
25B1 – Violent (police must secure)
25B2 – Threatening suicide
25B3 – Near hanging, strangulation or suffocation (alert)
25B4 – Unknown status (3rd party caller)
26A1 – No priority symptoms (complaint conditions 2-28 not identified)
26A2 to 28 – Non-priority complaints
26B1 – Unknown status (3rd party caller)
26B2 – Cardiac history (complaint conditions 2-28 not identified)
26D1 – Not alert
27A1 – Non-recent (=6 hours) peripheral wounds
27B1 – Non-recent (=6 hours) single central wound
27B2 – Known single peripheral wound
27B3 – Serious hemorrhage
27B4 – Unknown status (3rd party caller)
27D1 – Unconscious or arrest
27D2 – Not alert
27D3 – Central wounds
27D4 – Multiple wounds
27D5 – Multiple victims
28. Stroke (CVA)
28A1 – Breathing normally <35
28B1 – Unknown status (3rd party caller)
28C1 – Not alert
28C2 – Abnormal breathing
28C3 – Speech or movement problems
28C4 – Numbness or tingling
28C5 – Stroke history
28C6 – Breathing normally
29A1 – 1st party caller with injury to not dangerous part of body
29B1 – Injuries
29B2 – Multiple victims (one unit)
29B3 – Multiple victims (additional units)
29B4 – Serious hemorrhage
29B5 – Unknown status (3rd party caller)
29D1 – Major incident (aircraft, bus, subway, train, watercraft)
29D2 – High mechanism (all-terrain, auto-bike/motorcycle, auto-person, ejection, personal watercraft, rollover, vehicle off bridge/height)
29D3 – Hazmat
29D4 – Pinned (trapped) victim
29D5 – Not alert
30A1 – Not dangerous body area
30A2 – Non-recent injuries (=6 hours)
30B1 – Possibly dangerous body area
30B2 – Serious hemorrhage
30D1 – Dangerous body area
30D2 – Not alert
30D3 – Breathing abnormal
31A1 – Single or near fainting episode and alert <35
31C1 – Alert with abnormal breathing
31C2 – Cardiac history
31C3 – Multiple fainting episodes
31C4 – Single or near fainting episode and alert
31C5 – Females 12-50 with abdominal pains
31D1 – Unconscious (at end of interrogation)
31D2 – Severe respiratory distress
31D3 – Not alert
31E1 – Ineffective breathing
32. Unknown Problem (Man Down)
32B1 – Standing, sitting, moving or talking
32B2 – Medical alert notifications
32B3 – Unknown status (3rd party caller)
32D1 – Life status questionable
33A1 – Acuity I (no priority symptoms)
33A2 – Acuity II (no priority symptoms)
33A3 – Acuity III (no priority symptoms)
33C1 – Not alert (acute change)
33C2 – Abnormal breathing (acute onset)
33C3 – Significant hemorrhage or shock
33C4 – Possible acute heart problems or MI (heart attack)
33C5 – Acute severe pain
33C6 – Emergency response requested
33D1 – Suspected cardiac or respiratory arrest