Using the ICS-309 Communications Log:
The ICS-309 form is also called the Communications Log. It is used to document communications you receive and send during an incident. Each entry in the log should include:
A unique number for each communication you send and receive. (Write in both your message number (For a relay use the number from the originating station) and number and the message number specified by the destination station, once you receive it.
The time of the communication.
The sender and recipient call sign, tactical call, or other identifier.
A brief summary of the type of message. (Example: ACS-SitRep-Tree Down-Hwy 11, mm 4) The message form has the full message details.
Actions taken and results.*
The originating station assigns the "From" Message Number." This number stays the same as the message moves potentially through out its journey to the final destination.
Assigning a number to each communication helps us to keep a clear and sequential record. This can be crucial. When the frequencies get busy you may not be able to relay your message before a higher priority message comes in. The log helps you to maintain situational awareness, coordinate actions with others at your station, and keep a historical record for review and debriefing later.
For this Comex we are focusing on radio transmissions. In a real world incident the log might include telephone calls, satellite based text messages, and other forms of communication. Some communications are tactical, and have no associated form. Tactical communications such as "Campus Flooding. Shutting down station to evacuate to upper campus." might be transmitted to others on your frequency. All significant communications would be included on the ICS-309.
*The action is usually to relay a message towards its intended recipient. It can be helpful to indicate notes on the log to make sure you've done that. For example, you could Put a T to the right in the margin of each line to indicate that you successfully transmitted it, and an "R" to indicate you received the entire message. This is most helpful when you have another person working with you. For example, you might receive messages, write them on the form, and hand the form to another person who transmits it on a different frequency.
It is possible that due to conditions out of your control, you might not be able to relay the message. The lack of the mark is a reminder that perhaps you can go back to it and try again later when time and conditions permit.