## ASM (Application Specific Messages)

**Application Specific Messages (ASM)** are messages transmitted within AIS messages (messages 6 and 8) to convey specialized information beyond the scope of standard AIS messages.

Unlike standard AIS messages containing basic vessel data (identifier, coordinates, course, speed), ASM allow transmitting information necessary for navigation and vessel management tasks:

 - hydrological information;
 - meteorological information;
 - route information;
 - current values: weather, sea level, sea state, air gaps;
 - transmission of traffic management signals;
 - routes;
 - area notices, etc.

```{attention}
It should be noted that ASM are displayed only in ECDIS and Radar applications. ASM are not displayed on the AIS receiver screen.
```

#### Purpose of ASM

ASM provide:

- Prompt transmission of general or addressed information;
- Implementation of commercial services;
- Visualization of complex data;
- Reduction of time to obtain operational information;
- Transmission of significant navigation information faster than through traditional channels;
- Information about port status, berths, port entry times, and tidal windows helps plan routes and manage arrival times.
- Acquisition of data on hydrographic, hydrological, and meteorological events and their forecasts, as well as particularly hazardous hydrometeorological phenomena;
- Information about berths, available services, schedules, and special instructions facilitates port coordination and reduces idle time.

```{tip}
ECDIS automatically processes received ASM messages and displays them on the chart in a standardized format. To view and filter ASM messages, use the AIS target display settings.
```

#### Types of Processed ASM Messages

ECDIS processes the following **Application Specific Messages (ASM)**:

##### Port Operations Information

- **Clearance time to enter port** (DAC 1, FI 18) — port entry clearance with time indication
![](images/ASM_FI_18_1.png)
![](images/ASM_FI_18_2.png)
![](images/ASM_FI_18_3.png)<br>
- **Berthing data** (DAC 1, FI 20) — vessel berthing data
![](images/ASM_FI_20_1.png)
![](images/ASM_FI_20_2.png)<br>
- **Tidal window** (DAC 1, FI 14 and 32) — tidal window information
![](images/ASM_FI_32_1.png)
![](images/ASM_FI_32_2.png)<br><br>

##### Meteorological and Hydrographic Information

- **Weather observation report from ship** (DAC 1, FI 21) — weather observation report from vessel
![](images/ASM_FI_21_1.png)
![](images/ASM_FI_21_2.png)<br>
- **Meteorological and Hydrographic data** (DAC 1, FI 31) — meteorological and hydrographic data
- **Environmental** (DAC 1, FI 26) — environmental data
![](images/ASM_FI_26_1.png)
![](images/ASM_FI_26_2.png)<br><br>

##### Navigation Information

- **Marine traffic signal** (DAC 1, FI 19) — maritime traffic signals
![](images/ASM_FI_19_1.png)
![](images/ASM_FI_19_2.png)<br>
- **Area notice** (DAC 1, FI 22 and 23) — area notices (navigation warnings, restrictions)
![](images/ASM_FI_22_1.png)
![](images/ASM_FI_22_2.png)<br>
- **Route information** (DAC 1, FI 27 and 28) — route information
![](images/ASM_FI_27_1.png)
![](images/ASM_FI_27_2.png)<br><br>

##### Additional Information

- **Text description** (DAC 1, FI 29 and 30) — text descriptions and notes
![](images/ASM_FI_29_2.png)
