Atari ST: Quest for a DB-19 connector , the History
Somewhere in the distant past, someone at Atari Corp must have been thinking that it would be a briljant idea to to use a specific model Connector instead of the already quite standardized 25-pin D-sub connectors.
So the connector of choice became the D-sub 19 or DB-19, which appeared in a Female version on the back of the Atari ST line of computers, this connectors purpose was for ACSI support (Atari's version of SCSI). (Apple II Computers seem to use a DB19 connector also)
Atari ST: Quest for a DB-19 connector , becoming Unobtanium
When the Atari line of computers slowly neared extinction , so did the demand for that special plug too.
As a result, today if you want to connect something to the ACSI port of the Atari, you have to pay big bucks for an original (NOS or used) , or use some other kind of handcrafted connector.
There are different devices that use the ACSI port for connecting to the Atari computer, Most of them are storage solutions , nowadays based on SD card storage.
Atari ST: Quest for a DB-19 connector , Building an alternative
I really not have payed much attention to the DB19 , since i had nothing to connect it to, and therefore it was no deal that it was almost unobtanium to others.
And then a week ago a friend asked me if i could design and create a DB19 kind of connector for him, he wanted to try and hookup a RaSCSI device to the ASCI port and a DB19 was nowhere to be found.
It took me some 3 iterations before i had something that even surprised myself how well it looked and functioned.
Atari ST: Quest for a DB-19 connector , the options
There are various ways to create a DB-19 connector for connecting devices to the ACSI port of the Atari, one being a bit more spartan than the other.
Think of 3D printed connectors, which will give you a basic to start with, of course without the pins.
You will then have to order the exact size pins for the db-19 connector, separately and fiddle that into the 3D printed plug.
Another option is to use a PCB , solder the 19 Pins into the pcb and use that to connect to the ACSI port, the data is then transported through a IDC header on the same PCB, and a 20 pin ribbon cable.
It might be that on the other side of the IDC Cable, you have to do that again in the reverse order (idc to DB-19).
Third option (which I use myself) is to modify a DB25 plug so that it not only functions as a regular DB-19, but also looks like one.
The pins will be straight and of the exact dimension, the connector will fit properly, and if done well it even will fit a regular db19 Shell.

Atari ST: Quest for a DB-19 connector , the Product
And so, there it is, a handmade alternative to a genuine male DB-19 connector, i made a batch of 5 besides the one i made for a friend of mine.
Now i have them, i have no idea if they are filling a gap in some way, i assume time will tell.
For creating a single DB-19 connector with Hood , i have to disassemble a DB-25 connector, 3D print the connector part, and for the shell i had to design and print a custom Shell and had to strip a db-25 shell from it's screws and clamps to complete the 3D printed shell.
On top of the 3D printing of Shell and connector and the used parts comes labour, i really don't have a clue what a realistic price would be.