Johnathan Telin <telinj4615@clarkstate.cc.oh.us> notes that in the first level of Marathon there is reference to a "teleport terminal", a "jump pad", and a "Teleporter Pad Terminal". Johnathan asks:

Jump pad, teleport pad, teleport terminal, what is it??

Interesting point. When you arrive at the exit terminal on "Arrival" you find a light colored 'square' texture in front of it.

This exit terminal is designated as Hangar Area 5 Teleporter Pad Terminal<93.53.211.53>

Could the light colored 'square' be the "jump pad" or "teleport pad"?

On the next level, "Bigger Guns Nearby", note what you're standing on when you arrive (start).

The light colored 'square' is the same as the one at the exit terminal on "Arrival". Was this supposed to represent a "destination" pad?

However there is no "jump pad" looking square at the exit terminal on "Bigger Guns Nearby".

Was the idea of "jump pads" dropped?

Johnathan Telin <telinj4615@clarkstate.cc.oh.us> provides further evidence to suggest that "jump pad" areas were originally intended in Marathon as evident from "Arrival" but then dropped:

Also to further back this up, remember in the first terminal on Bigger Guns Nearby? There was no light-colored square in front of it and Leela says that you have to get to that other one so she can teleport you out because she can't do it from this one. Well why can't she? Because there is no "pad"? An original Bungie idea that was later dropped due to time wasted through implementation?

The same could be said for the first terminal on Arrival. There is no "jump pad" area in front of the terminal and Leela tells you to locate the one in the Hangar's control room.

Brett Trent <vector@cutco.com> writes:

I was thinking, unless I misunderstand this issue completely, is it not possible that Bungie dropped the Jump Pad concept simply because it would have made it way too easy for the player to identify a particular terminal as an exit point?

I can recall many happy hour running 'round levels re-reading all the terminals unsure of which would now deliver me to the next level.

Patrick Coan <damnglitch@gmail.com> writes:

I find it a bit of a shame that they dropped Jump Pads so shortly into the game. While it is perhaps probable that they dropped the concept because it made finding the exit terminal easier, I attribute it mostly to laziness!

Anyway, I digress. The reason I find it to be a shame is that by Habe Quiddam, Durandal reveals that he has discovered how to increase the power of the Marathon's transporters.

"I have learned from the S'pht many things. One of them is a
complex software enhancement that allows me to extend the
power and distance of the Marathon's teleporters. This
enhancement also removes the need for destination apparatuses."

So midway through the game, you have an in-story reason as to why jump pads are not required. There is not only this, but in the very next level (Neither High nor Low) he introduces the idea of teleporter beacons that must be locked onto.

"Stop in front of a window. If you stop and are not
teleported, then either I can't lock onto your teleport
beacon, or else I feel you haven't explored the area
thoroughly enough."

Given the marathon's technique of teleporting, there's not much of a use for beacons; supposedly a pad is required. But ah! Durandal doesn't need a pad, but a beacon. Remember the Alien Converter device? Maybe, before placing pads became a hassle, that was intended to be a beacon!

"You should go to this location
and retrieve a device that the
S'pht have provided for us.
It will allow you to slay more
Pfhor. Does that make you
happy?"

...Like being able to to beam to the ship (and then back), where there are very many pfhor indeed.

" I could let you leave without it, but you'd be sorry later."

...like, for instance, if you were stranded on a the pfhor ship.

Stop in front of a window. If you stop and are not
teleported, then either I can't lock onto your teleport
beacon, or else I feel you haven't explored the area
thoroughly enough.

In terms of game mechanics, the alien power converter is largely a macguffin; an object to find merely to drive the player to action. It serves no actual purpose. Maybe before jump pads were de-emphasized, it was merely a macguffin with a different name? It seems odd that the spht or the pfhor would have a device that allowed YOU to use THEIR systems, of course, I suppose it could be omni directional, or modified by the spht.

Patrick raises some interesting points. The fact that Durandal makes reference (on Habe Quiddam) to no longer needing "destination apparatuses" further reinforces the plot concept of jump pads. However, while we arrive (start) on a jump pad on Bigger Guns Nearby (see pic above) this is not the case on the next level or indeed subsequent levels. The whole concept of jump pads is suddenly dropped. Yet here is Durandal, half way through the game, making reference to now no longer needing jump pads. Perhaps someone should have told him earlier ;-)

And what of our teleport beacon?

Stop in front of a window. If you stop and are not
teleported, then either I can't lock onto your teleport
beacon, or else I feel you haven't explored the area
thoroughly enough.

Did we always have one? Or as Patrick suggests above, could this have been a possible early function for the device provided to us by the S'pht on Habe Quiddam. If the former, then we might question why we had one in the first place since based on the plot it was not possible to teleport on the Marathon without a jump pad (Teleporter Pad Terminal) or an automatic teleporter. Marathon (human) technology didn't appear to be sufficiently advanced to warrant the existence of teleport beacons. Then again perhaps our creators planned in advance? :-)

Lastly, what was the function of the Alien Energy Convertor? The Story Page's FAQ has this to say on the subject:

What does the Alien Energy Converter do?

From a game-play point of view it allows you to complete "Habe Quiddam" successfully. If you don't pick it up you can't get off the level. The Alien Energy Converter is never used after "Habe Quiddam" nor is it needed to complete any later levels as the Command-Option Begin New Game function easily demonstrates. From a story point of view the Alien Energy Converter is supposed to allow you to kill more Pfhor. Durandal says at the beginning of "Habe Quiddam":

You should go to this location
and retrieve a device that the
S'pht have provided for us.
It will allow you to slay more
Pfhor. Does that make you
happy?

After we retrieve the device Durandal tells us that we will soon be going further afield. The ultimate destination is of course the Pfhor scoutship. We might assume from this that the Alien Energy Converter is needed while we are on the Pfhor ship. Some people have speculated that the Converter would be needed to interface with the alien shield rechargers and/or pattern buffers. Equally it might have some role in allowing us to use the Enforcer's alien weapon. Its exact function in terms of the story is still unknown.

Interestingly, the Original Level Notes for Marathon refers to this device as an 'Alien Interfacer'.

Oddly, it is given to us by... well that's another story. ;-)