SR wrote:

Because of this can this radio make some kind of transmission?

Could someone please explain this to me in layman terms.

No, it can not transmit. The "TR-REC-CAL" just provides a switch closure
that you can use to put a separate transmitter in the transmit mode.
Your "break-in" plug is a hook up for a relay that usually ties in with
your antenna change over relay, a device that switches your one antenna
between the separate transmitter and the receiver. It is an "interlock"
scheme, if you will, that "mutes" or locks out the receiver when you
turn on your transmitter (to keep from blowing out the front end of your
receiver while transmitting).

A careful look at the hook up diagram in your manual should clarify this
a bit more.