ARRL REPEATER OPERATION
From The ARRL Operating Manual

1) Monitor the repeater to become familiar with any peculiarities in its operation.  Each repeater is a different kingdom and many have specific and in some cases unwritten rules that apply--it's always best to listen for a while before jumping into the fray.

2)  To initiate a contact simply indicate that you are on frequency.  Various geographical areas have different practices on making yourself known, but generally "This is NU0X monitoring." will suffice.  Please don't kerchunk (key up without identifying yourself) the repeater just to see if it's working.  This procedure is annoying to other users.  Taken a step too far, it may trigger the control operator to shut off the machine!

3) Identify legally.  You must identify at the end of a transmission or series of transmissions and at least once each 10 minutes during the communication.  This is the FCC rule.

4) Pause between your transmissions.  Sometimes the repeater will have a beep tone to indicate the appropriate pause for you.  This allows other hams the opportunity to use the repeater (someone may have an emergency).  On many repeaters a pause is necessary to reset the time-out timer.

5)  Keep transmissions short and thoughtful.  Your monologue may prevent someone with an emergency from using the repeater.  If you talk long enough, you may actually time out the repeater.  Something else to keep in mind is that your transmissions are being heard by non-hams who can pick them up on most VHF/UHF public service scanners.  Remember that you are an ambassador from Amateur Radio operators and they will be judged on your behavior.  Please don't give a bad impression of our service to others.

6) Use simplex whenever possible.  If you can complete your QSO on a direct frequency, there is no need to tie up the repeater and prevent others from using it.  In most areas the initial contact can be on the repeater.  The conversation can then migrate to an agreed-upon simplex frequency.

7) Use the minimum amount of power necessary to maintain communications.  This is required by FCC rules, and it reduces the possibility of accessing distant repeaters on the same frequency.  In general, by the nature of the beast, you won't need a 60-W radio to access a local repeater.

8)  Don't break into a contact unless you have something to add.  Interrupting is no more polite on the air that it is in person.

9)  Repeaters are intended primarily to facilitate mobile operation.  During commuter rush hours, home stations should relinquish the repeater to mobile stations; some repeater groups have rules that specifically address this practice.

10)  Many repeaters are equipped with autopatch facilities which, when properly accessed, connect the repeater to the telephone system to provide a public service.  Although amateur operators may not accept compensation for the use of their radios, under certain conditions the radio/autopatch can be used to make appointments and order items.  This is a decision made by the local repeater owner, however, so check with yours before making such calls.  Autopatch facilities should never be used to avoid a toll call or where regular telephone service is available.  Remember, autopatch privileges that are abused may be rescinded.

11)  All repeaters are assembled and maintained at considerable expense and effort.  Usually an individual or group is responsible, and those who are regular users of a repeater should support (yes, probably financially...) the efforts of keeping the repeater on the air for all to use.