Take the scanner apart so you can see the circuit boards and figure where you are going to mount the chassis jack. if the scanner can be tapped there will be a solder pad on the board that says "disc", use that pad to use for the discriminator tap.
When you have the scanner apart, look for the numbers on the chip(s). That website list the receiver chips. https://www.discriminator.nl/ic/index.html
You may find your IC on there and go from there. Only problem on some older scanners is they don't support the band plan changes and you can't enter the exact frequency you may want. I find it interesting to find old scanners at thrift stores or garage sales and tap them.
The SDS200 doesn't have any discriminator point, it's totally digital in microprocessors. By the time it's converted to analog audio it's already filtered to feed the analog audio circuits. But there might be a way to get a digital stream from the scanners discriminator. I know that Uniden had a driver for the HP1/2 scanners that made it possible to use the digital stream but I don't know if it actually where someone that made a program to use that data.
Remove both covers and look at the bottom of the board. A test point is marked 'disc'. Find a suitable location on the back panel for a 3.5 MM stereo jack. Mount the jack, solder L&R together with a 100K resistor, one end. Use such as audio coax, hots to the loose end of the resistor.
The other end hots, solder to the DISC test point. Reassemble the scanner. The purpose of the resistor is to neutralize the DC component at the discriminator. Varies + - with frequency. You will need an outboard audio preamp to get a 1V P-P signal for the computer line input.
This should work great for DSD, Multipsk or what ever decoding software you are using.
What I did with my scanner and works like a charm.