PMA-2 is mounted on the forward port of the Harmony connecting node, and was used when Space Shuttle orbiters docked at the ISS.
It was outfitted with Station-to-Shuttle Power Transfer System (SSPTS) hardware to allow the shuttles to stay docked longer to the space station.

PMA-2 has been moved several times as part of the ongoing space station assembly process.
It was originally connected to the forward hatch of Unity, but when STS-98 delivered the Destiny module in February 2001, PMA-2 was moved to the berthing ring of the Z1 truss so that Destiny could be berthed to the forward hatch of Unity.
PMA-2 was finally moved to the forward hatch of Destiny. (
The removal of PMA-2 from Unity was the first time the CBM had been used to disconnect two ISS components.)
After STS-120 had delivered Harmony to the space station in October 2007, Canadarm2 repositioned PMA-2 at the forward port of Harmony on November 12, 2007.
Two days later, the combined package of Harmony and PMA-2 was moved to its final location, the forward hatch of Destiny.
As of 2020, PMA-2 is expected to stay berthed at the forward port of Harmony for the remaining duration of the ISS.

When a shuttle docked with the station, its "final approach [was] at a relative velocity of one-tenth of a foot per second. [
As it made] contact with Pressurized Mating Adapter 2 [latches] automatically attached the two spacecraft together.
Once relative motion between the spacecraft stopped, [a Shuttle astronaut retracted] the docking ring on [the Shuttle's] mechanism, closing latches to firmly secure the shuttle to the station."

On July 18, 2016, International Docking Adapter-2 was launched on SpaceX CRS-9.
It was attached and connected to PMA-2 during a spacewalk on August 19, 2016.
PMA-2 is mounted on the forward port of the Harmony connecting node, and was used when Space Shuttle orbiters docked at the ISS. It was outfitted with Station-to-Shuttle Power Transfer System (SSPTS) hardware to allow the shuttles to stay docked longer to the space station.
PMA-2 has been moved several times as part of the ongoing space station assembly process. It was originally connected to the forward hatch of Unity, but when STS-98 delivered the Destiny module in February 2001, PMA-2 was moved to the berthing ring of the Z1 truss so that Destiny could be berthed to the forward hatch of Unity. PMA-2 was finally moved to the forward hatch of Destiny. (The removal of PMA-2 from Unity was the first time the CBM had been used to disconnect two ISS components.) After STS-120 had delivered Harmony to the space station in October 2007, Canadarm2 repositioned PMA-2 at the forward port of Harmony on November 12, 2007. Two days later, the combined package of Harmony and PMA-2 was moved to its final location, the forward hatch of Destiny. As of 2020, PMA-2 is expected to stay berthed at the forward port of Harmony for the remaining duration of the ISS.
When a shuttle docked with the station, its "final approach [was] at a relative velocity of one-tenth of a foot per second. [As it made] contact with Pressurized Mating Adapter 2 [latches] automatically attached the two spacecraft together. Once relative motion between the spacecraft stopped, [a Shuttle astronaut retracted] the docking ring on [the Shuttle's] mechanism, closing latches to firmly secure the shuttle to the station."
On July 18, 2016, International Docking Adapter-2 was launched on SpaceX CRS-9. It was attached and connected to PMA-2 during a spacewalk on August 19, 2016.
Pressurized Mating Adapter