The TE 1658610-3 is a 15-position D-Sub receptacle from the AMPLIMITE HDF-20 series, terminated via IDC to a ribbon cable rather than the usual solder cups or crimp contacts. That IDC termination is the whole point — it lets you mass-terminate a 15-conductor ribbon in one press stroke instead of landing each wire one at a time.
This connector accepts 26-28 AWG stranded or solid wire.
This is a female (receptacle) D-Sub with 15 positions in a standard DA-15 shell layout. The pinout follows the standard D-Sub assignment: two rows of 7 and 8 contacts, with the rows offset by half the 0.108-inch pitch. The 4-40 threaded inserts are on the housing flanges for the mating jackscrews. If you're replacing a solder-cup or crimp-contact D-Sub in an existing harness, the IDC termination changes the cable preparation but the mating interface is identical — it will mate with any standard DA-15 male plug.