When you pass written traffic by radio you will meet three common formats: the ARRL Radiogram used by the amateur National Traffic System, the ICS-213 General Message used on incidents, and the ACP-127 message used by MARS. The message is the same; the wrapper around it changes.
This page compares the three, then walks through each one part by part. When you are ready to practise, the free Message Formatter & Traffic Log lays out one message in all of them.
On this page
The Three Formats at a Glance
| ARRL Radiogram | ICS-213 | MARS (ACP-127) | |
|---|---|---|---|
| Used by | Amateur radio operators passing traffic on the National Traffic System (NTS) | Incident personnel working in the Incident Command System (ICS); FEMA publishes the form | Military Auxiliary Radio System (MARS) stations |
| Parts | Preamble, address, text, signature | Ten numbered blocks | Numbered format lines: heading, BT, text, BT, end of message |
| Precedence | Routine, Welfare, Priority, Emergency | No precedence block on the form | R (Routine), P (Priority), O (Immediate) |
| Length | Text 25 words or less, if possible | As concise as possible | No line longer than 69 characters; long messages are split into pages |
| Reply | A new radiogram back (HXE asks the delivering station to get one) | Blocks 9 and 10 on the same form | — |
ARRL Radiogram
The Radiogram is the standard message of the amateur National Traffic System. ARRL’s form instructions (FSD-218) say every formal radiogram should contain four parts, in this order.
1. Preamble
| Field | What goes in it |
|---|---|
| Number | The message number. Begin with 1 each month or year. |
| Precedence | R, W, P or EMERGENCY (see below). |
| Handling instructions (HX) | Optional (see below). |
| Station of origin | The call sign of the first amateur to handle the message. |
| Check | The number of words or groups in the text only, not the address or signature. |
| Place of origin | Where the message came from. This is not necessarily where the station of origin is. |
| Time filed | Optional with the originating station. |
| Date | Must agree with the date of the time filed. |
2. Address
As complete as possible, including the zip code and telephone number.
3. Text
Limit it to 25 words or less, if possible. X is used in place of a full stop (sent as X-ray on phone). If the text uses an ARL numbered message, the number is spelled out and ARL goes in front of the check. See ARL Numbered Radiograms.
4. Signature
The name of the person sending the message.
Precedence
- EMERGENCY
- Life-and-death urgency, sent by amateur radio when regular commercial facilities are not available. Always spelled out. When in doubt, do not use it.
- PRIORITY (P)
- Important messages with a specific time limit, official messages not covered by Emergency, and notifications of death or injury in a disaster area.
- WELFARE (W)
- An inquiry about the health and welfare of someone in a disaster area, or an all-is-well message from the area. Handled after Emergency and Priority but before Routine.
- ROUTINE (R)
- Most traffic in normal times. In a disaster it is handled last, or not at all when circuits are busy.
Handling instructions (optional)
| HX | Meaning |
|---|---|
| HXA | (Followed by a number) Collect landline delivery authorised by the addressee within that many miles. No number means unlimited. |
| HXB | (Followed by a number) Cancel the message if not delivered within that many hours of filing; service the originating station. |
| HXC | Report the date and time of delivery to the originating station. |
| HXD | Report to the originating station who you received it from and who you relayed it to, with dates and times, or the date, time and method of delivery. |
| HXE | Delivering station: get a reply from the addressee and originate a message back. |
| HXF | (Followed by a number) Hold delivery until that date. |
| HXG | Delivery by mail or landline toll call not required. If there is a toll or other cost, cancel the message and service the originating station. |
An example
A short, made-up radiogram as you would copy it, one part per line:
NR 1 R HXG N0CALL 9 ANYTOWN CO 1830Z OCT 31
ALEX HARPER
123 MAIN ST
ANYTOWN CO 80000
555 555 0100
BT
ARRIVED SAFELY X CALL WHEN YOU CAN X LOVE
BT
JORDAN
The check is 9 because the text has nine words, counting each X.
On phone: use prowords instead of prosigns. You don’t need to name each part as you send it. Finish with “End of Message”, then “More” if another message follows or “No More” if it is the last one. Spell difficult or unusual words phonetically, but not common words, and don’t use CW abbreviations or Q signals on phone.
Our NTS Radiogram Form page goes into the form in more detail.
ICS-213 General Message
The ICS-213 is the general message form of the Incident Command System. FEMA’s instructions say it is used to record incoming messages that can’t be passed on by voice, and by the Incident Command Post and other incident staff to send messages to the Incident Communications Center for transmission by radio or telephone. It is used for any message that needs hard-copy delivery.
| Block | Title | What goes in it |
|---|---|---|
| 1 | Incident Name (Optional) | The name assigned to the incident. |
| 2 | To (Name and Position) | Who the message is for: at least the first initial and last name, and their position. For Unified Command, include agency names. |
| 3 | From (Name and Position) | Who is sending it, in the same way. |
| 4 | Subject | The subject of the message. |
| 5 | Date | Month/day/year. |
| 6 | Time | 24-hour clock. |
| 7 | Message | The content. Be as concise as possible. |
| 8 | Approved by | Name, signature and ICS position/title of the person approving the message. |
| 9 | Reply | The recipient writes a reply and returns it to the originator. |
| 10 | Replied by | Name, ICS position/title and signature of the person replying, with the date and time. |
On paper the ICS-213 is a three-part carbon form. The sender completes Part 1 and sends Parts 2 and 3 to the recipient, who completes Part 2 and returns Part 3 to the sender. A copy goes to the Documentation Unit.
For the ICS-213 sent digitally through the NTS, ARRL’s ICS-213 data dictionary says to put SAME in Approved by when it is the same person as the signature, and SAME for the Replied by name and position when they match.
Download the fillable form from FEMA: ICS Form 213, General Message (PDF).
MARS (ACP-127) Message
MARS stations prepare messages using ACP-127 procedures, as supplemented for the United States. An ACP-127 message is built from numbered format lines, and each line has strict rules so that relay stations and automated systems can read it. The overview below follows a MARS training paper on ACP-127 procedures by Daniel V. Wolff, Jr. of Army MARS.
| Line | What it holds |
|---|---|
| 1 | Transmission identification: V, then the start-of-message signal ZCZC, the channel indicator and a three-digit transmission serial number. |
| 2 | Precedence and the routing indicators of the destination. |
| 3 | DE, the originating station’s routing indicator, the message serial number and the Julian date and time it was released. |
| 4 | Security warning: ZNR UUUUU (may go by radio unchanged) or ZNY EEEEE (unclassified, but must be encrypted before it goes by radio). |
| 5 | Precedence and the date-time group (DTG). |
| 6 | FM and the originator’s plain language address. |
| 7 and 8 | TO and INFO addressees: routing indicator / plain language address. |
| 9 | XMT: an addressee exempted from a collective address. |
| 11 | BT: separates the heading from the text. |
| 12 | The text. The first line is the classification, such as UNCLAS. No line may be longer than 69 characters. |
| 13 | BT: separates the text from the ending. |
| 15 | The station serial number from line 3, after a # sign. |
| 16 | NNNN: end of message. |
Lines 10 and 14 are normally left out of a plain message. MARS uses three precedences: R (Routine), P (Priority) and O (Immediate). The DTG is two digits for the date and four for the time, then Z, the first three letters of the month and the four-digit year, for example 031821Z FEB 2014.
The middle of a message looks like this (routing indicators and call signs left out):
R 311830Z OCT 2026
FM ARMY MARS STATION (call sign)
TO (routing indicator)/(addressee)
BT
UNCLAS
(text)
BT
Routing indicators and MARS addresses come from MARS publications, and messages containing FOUO or personal information must be encrypted before transmission. This section is an overview so you can recognise a MARS message. MARS members follow ACP-127G, its U.S. supplement and their branch’s publications.
Read more about the program itself on our Military Auxiliary Radio System (MARS) page.
Practise With the Message Formatter
The free Message Formatter & Traffic Log takes one message and lays it out as an ARRL Radiogram, an ARL numbered Radiogram, an ICS-213 or a simplified MARS message, and keeps a log of what you send and receive. It runs in your browser and works offline.
Message Formatter & Traffic Log
Free download. No install, no account.
Sources
More on passing messages by radio is in Message Handling & Reporting Formats.
Message HandlingRemember, Fortune Favors the Prepared
Semper Paratus, Semper Gumby