CRTs evolved over time. Every year they got bigger and faster. Faster CRTs, by definition, display more lines. Several different arcade monitor standards came about because of this evolution, each one supporting more lines. They are listed below.

Standard Resolution = 262 lines refreshed 50 - 60 times per second
Extended Resolution = 312 lines refreshed 53 times per second
Medium Resolution = 416 lines refreshed 50 - 60 times per second

It needs to be pointed out that the number of lines listed above represent the total number of lines used to draw a display, which, as we now know, includes both active lines (lines that display data) and blanking lines (buffering time for the CRT). With this information in hand, we can now define a fair amount of arcade monitor jargon.

Since arcade monitors are defined by their fastest operating speed, we get the following.

Standard Resolution = 262 lines x 60 per second = 15720 lines per second
Extended Resolution = 312 lines x 53 per second = 16536 lines per second
Medium Resolution = 416 lines x 60 per second = 24960 lines per second

And since measurements in "per seconds" are usually given in hertz (Hz), we can convert the above calculations into the more technically familiar ones listed below.

Standard Resolution = 262 lines x 60 Hz = 15.7 kHz
Extended Resolution = 312 lines x 53 Hz = 16.5 kHz
Medium Resolution = 416 lines x 60 Hz = 25 kHz

If you've ever read about arcade monitors before, then these numbers should look familiar. In fact, its quite common to refer to arcade monitors by their horizontal clock rate (the number of lines a CRT draws per second). You should now also understand that a 15.7 kHz arcade monitor, by definition, can draw up to 15,700 lines per second and that a 25 kHz arcade monitor, by definition, can draw up to 25,000 lines per second (from the above calculations, you should also realize that these numbers are rounded approximations).

In order to perfectly emulate every arcade game we need to be able to run the following

262 lines (192 active + 70 blanking) x 60 Hz = 15.7 kHz (a few games)
262 lines (224 active + 38 blanking) x 60 Hz = 15.7 kHz (most games)
262 lines (240 active + 22 blanking) x 60 Hz = 15.7 kHz (many games)
416 lines (384 active + 32 blanking) x 60 Hz = 25.0 kHz (a few games)
525 lines (480 active + 45 blanking) x 60 Hz = 31.5 kHz (vector games)

The first 3 modes, x192, x224, and x240, all run on 15.7 kHz arcade monitors. Most arcade games run at 224 lines, although more modern ones typically use 240 lines. This is simply because newer 15.7 kHz arcade monitors use faster, more accurate components. Consequently, they require fewer blanking lines (buffering time for the CRT), meaning they can display higher resolution games.

The 5th mode down, x384, runs on a 25 kHz arcade monitor. 25 kHz arcade monitors, for what every reason, were never enormously popular with arcade game developers (mostly likely due to their cost). So only a couple of games use 384 line modelines, games like 720 degrees. And the last mode, x480, is really an adaptation for vector game emulation on raster CRTs (recall that vector games used special vector CRTs to draw images). There are a couple of weirdo modes that I failed to cover, but for right now we'll just pretend they don't exist (as most games use the ones above).

From the above modes, the x224 and the x240 ones command the most attention, as 85% - 90% of all arcade games use one of these two modes (this is just an educated guess).

If we recklessly wield a little algebra, we obtain the following definitions / formulas.

Horizontal Clock = Number of Lines (active + blanking) x Refresh Rate
Refresh Rate (or Vertical Clock) = Horizontal Clock Rate / Number of Lines (active + blanking)
Number of Lines (active + blanking) = Horizontal Clock Rate / Refresh Rate

Pixel Clock = Number of Pixels (active + blanking) x Number of Lines (active + blanking) x Refresh Rate
Pixel Clock = Number of Pixels (active + blanking) x Horizontal Clock

If we know the resolution and the refresh rate of an arcade game, then it's fairly easy to calculate what kind of monitor it used. So, for example, if we wanted to know what kind of monitor the Mortal Kombat series ran on, all we would need to do is obtain the resolution and refresh rate of the game. This is a fairly easy task in MAME, as the information is given when you start the game. In this case, it's 400x254 at 53.2 Hz. With this information in hand, we just plug and chug through the numbers.

(Active Lines x Refresh Rate) / Total Number of Lines = % Active Lines

254 lines x 53.2 Hz = 13619.2 total number of active lines

Since the lowest 25kHz resolution is 384 lines, we can easily deduce that MK runs on a 15.720 kHz CRT, so

13512.8 active lines / 15720 lines = 86% active lines

From our list below we can see that 85% is the closest mode.

192 active lines / 262 total number of lines = 73%
224 active lines / 262 total number of lines = 85%
240 active lines / 262 total number of lines = 91%
384 active lines / 416 total number of lines = 92%

So, we can now safely conclude that the Mortal Kombat series was designed for a CRT that ran the popular mode

262 lines (224 active + 38 blanking) x 60 Hz = 15.7 kHz

This information also tells us that if we configure a 15.7 kHz arcade monitor for

262 lines (240 active + 22 blanking) x 60 Hz = 15.7 kHz

that all the Mortal Kombat games will have either the incorrect refresh rate, require stretching, or will have borders, depending upon your setup. Likewise, it also lets us know that if we configure a 15.7 kHz arcade monitor for

262 lines (224 active + 38 blanking) x 60 Hz = 15.7 kHz

that all the Mortal Kombat games will run true to the originals, with the correct refresh rate and no borders or stretching. So what's the best mode to run a 15.7 kHz monitor at?

If your 15.7 kHz monitor supports both modes (which it should) then it really depends on where your preferences lie. If you choose x224 at 60 Hz then more of your games will be in vertical synchronization. If you choose x240 at 60 Hz, then vertical games (run horizontally) will look nicer, especially many older ones, like pacman, mappy, galaga, etc. Why?

Well, all of these games used 288 columns, and if you play a vertical game on a horizontal monitor, then the columns become rows, so 288 columns becomes 288 rows. And if we do a little math

(15720 lines / (50 - 60)Hz) x 91% active lines = 288 - 240 lines

we find that a 240 line setup can run all of your favorite < 288 column vertical games on a horizontal monitor. Granted, they won't be at the correct refresh rate, so your games will be out of vertical synchronization, but at least none of the games require line whacking or interlacing. If you choose 224 lines at 15.7 kHz then you have a range of

(15720 lines / (50 - 60)Hz) x 85% active lines = 268 - 224 lines

As you can see, 288 column vertical games take a whacking here, 20 lines need removing. But if your willing to push your vclock down to 47 Hz, then

(15720 lines / (47 - 60)Hz) x 85% active lines = 286 - 224 lines

all your 288 column games look groovy again. If you did the same thing on a 240 line setup, you'd max out at 306 lines. Naturally, the reverse of all this holds true if you run horizontal games on a vertical monitor.

With a few more calculations we can also see that

240 lines x 60 Hz - 224 lines x 60 Hz = 1 kHz

a 1kHz horizontal clock range enables us to perfectly emulate any game between 224 - 240 lines.

It would take a hard core amount of underclocking, overclocking to get 192 line modes, so these games will either be stretched or have borders. Be aware that the border hit is large here. On a 240 line setup, around 20% of your screen (192 / 240 = 80%) and on a 224 line setup around 15% of your screen (192 / 224 = 85%).

In order to emulate the two last modes on a 15.7 kHz monitor, you'll need to half the games refresh rate to 25Hz - 30Hz (i.e. interlace), which will just double the number of lines at any hclock, so if you have a typical 240 line setup then you will have the following interlace range

2 x (288 - 240) lines = 576 - 480 lines

Notice that this takes care of vector games quite nicely, but that 384 line modes will also require stretching or borders (be aware that the border hit is large here, around 20% of your screen (384 / 480 = 80%).

But what if happens if you run all these modes on a 25 kHz monitor?

Well, on an ordinary 25 kHz arcade monitor we have the following range to work with

(24960 lines / (50 - 60)Hz) x 92% active lines = 460 - 384 lines

Obviously, a 25 kHz CRT can perfectly emulate 384 lines with

416 lines (384 active + 32 blanking) x 60 Hz = 25.0 kHz

But what of the other four modes?

192 line modes run perfectly double scanned or double pixeled (192 lines x 2 = 384 lines). Vector games will require some line sacrifices, however. Around 20 lines need to be whacked (480 - 460 = 20). If you underclock your refresh rate to 48 Hz, though, then you won't have to sacrifice any lines

(24960 lines / 48 Hz) x 92% = 480 lines

For the same reason, underclocking to 48Hz means all your 240 line games will run well double scanned (or double pixeled), though, obviously the vertical synchronization will be off. If you want your 240 line games in vertical sync, then you'll have to stretch them or take on a huge border, almost 40% of your screen (240 / 384 = 62%). 224 line modes run great double scanned at 448 lines, but like 240 line modes, if you want vertical sync you'll have to stretch them or take on an even larger border, slightly over 40% (224 / 384 = 58%).

How do you configure all of these modes to run on a D9200?

First off, the listed specifications for the D9200 on Wellsgardner's web site are a little misleading / confusing. The D9200 supports arcade boards that operate between 15.75 - 31.5kHz, but it does not support the entire range 15.75 - 31.5kHz. The D9200 is really a fixed frequency monitor that supports hclocks at 15.75kHz, 25kHz, and 31.5kHz with a 1-2kHz error margin at each frequency. This error margin varies from D9200 to D9200, as some D9200 owners have reported success with frequencies mine can't handle. It's only fair to say, that mine was one of the very first ones off the line. When I ordered it, they hadn't even started production.

From the above calculations we know that a 1 kHz horizontal clock range will enable us to emulate any mode between 224 and 240 lines. This means that on the D9200 you need to a 1 kHz hclock range near 15.75 kHz. How far you choose to push your monitor is up to you, but from the conversation I had with the engineer at Wellsgardner I feel quite safe with a 1.5 kHz range at each popular hclock. So with this in mind, I chose the following setup.

192 x 60 Hz = 13 kHz (doublescaned to 384 lines at 26 kHz)
224 x 60 Hz = 15.25 kHz
262 lines (230 active + 32 blanking) x 60 Hz = 15.72 kHz (reference mode)
240 x 60 Hz = 16.3 kHz
384 x 60 Hz = 26.0 kHz (reference mode)
480 x 60 Hz = 32 kHz (reference mode)

pclock 6-90
hclock 15.25 -16.75, 24-26, 31-32.
vclock 50-90

If you know much about emulation, the above numbers pretty much speak for themselves. Only one mode is not perfectly emulated, and that's x192 which is just double scanned. If you bring your lower hclock range up to 16.75 kHz, you will also get all the weirdo modes that operate over 240. There aren't many, but my D9200 handles them quite nicely, and, like I indicated earlier, mine was one of the first ones off the line.

Also, some are saying that they can run their Windows setup at 800x600. I don't really recommend this, as this overclocks the D9200 well beyond 1-2kHz.