How does a department use MABAS?
Each participating department develops a set of "box cards", which physically list out what equipment from neighboring towns the department will need to handle a specific emergency.    The box cards have several different levels, so as an incident requires more manpower, and next level on the card can be requested.

Are there different types of Box Cards?
Yes, there are cards for structure fires, EMS incidents, hazardous materials incidents, technical rescues, water rescues, and brush fires.    Besides there being different types of box cards, most departments have multiple box cards for each type of response, broken down by geographical districts within the department.

How is a MABAS request sent?
The agency in need of assistance will contact their local MABAS dispatch center.  Usually this is a larger center nearby that has the infrastructure and manpower to dispatch a major alarm and get the appropriate resources going.

How is the dispatch made?
All requests for a MABAS alarm are broadcast on 154.265, which is known is IFERN, standing for Interagency Fire Emergency Radio Network.    Mutual aid units due to the MABAS alarm contact the MABAS dispatcher on this frequency, and can request routing and staging information also on this frequency.    Fireground operations are NOT to take place on IFERN.   IFERN's purpose is to announce the alarm and get companies enroute to the emergency.

How do the different departments coordinate fireground radio operations?
This has been a difficult scenario since so many departments radio systems differ so vastly.   Recently MABAS issued an interoperability statement, calling for the following fireground channels to be common.
153.830 - Fireground RED
154.280 - Fireground WHITE
154.295 - Fireground BLUE

The current problem is with departments who operate on trunked systems which contain their own fireground channels.   In the event of a major emergency with vast mutual aid companies, communication on the fireground will be a disaster.

Fireground channels are used for low-power communication on the fireground, with dispatch operations on separate channels.   When responding units arrive on the scene of an incident, they then switch to fireground and announce they are on scene.

What are the different levels of alarm?
Alarms on the Box Card start at the "Box Alarm" level.   From there is a "2nd Alarm", "3rd Alarm", "4th Alarm", and in most cases a final "5th Alarm"    Requests for assistance above a 5th Alarm will require what is known as an "Interdivisional Box" where equipment is requested from neighboring MABAS Divisions.   The stricken department will need to specify how many units they are requesting.

How is an incident secured?
Once an incident is done and under control, the incident commander will contact the MABAS dispatcher and request an alarm be "struck-out".   A dispatch similar to the initial dispatch is made, this time announcing the alarm has been "struck-out".

More MABAS information
http://www.mabasradio.org/ - homepage of the MABAS organization
http://www.n9jig.com/radio/mabas/mabashq.html - Rich Carlson's very informative MABAS page