And the pinout for the HR2510 is?

OK, OK, Hang on here, this schematic (for the HR2510) is none too clear, but
here goes:

1. connector is a 5 pin "din" connector.
2. PTT switch uses both halves (but only one "throw") of a DPDT switch.
3. Both mic element leads are switched. One half of the switch connects one
mic lead to pin ONE (when pressed) (mic audio out)
4. The other half of the switch is in the "ground" circuit and is the PTT
lead. One pole of this switch half connects directly to pin THREE. (that'd
be the PTT circuit)
5. The second pole of this last switch is circuit "ground", and connects to
three different things. (a) remaining mic lead (b) one end of both the "up"
and "down" switches (c) connector pin TWO ground
6. That leaves two more connector pins, 4 & 5. FOUR is connected to the
remaining side of the "up"
switch. FIVE is connected to the remaining side of the "down" switch.

QSL?

Lynn, W7LTQ