Quoting the cards first for easy refferense:
Cassian: During the System Phase, you may choose 1 enemy ship at range 1-2 and guess aloud a bearing and speed, then look at that ship's dial. If the chosen ship's bearing and speed match your guess, you may set your dial to another maneuver.

INformant : Setup: After placing forces, choose 1 enemy ship and assign the Listening Device condition to it.

Listening Device: During the System Phase, if an enemy ship with the Informant upgrade is at range 0-2, flip your dial faceup.

1) When is the condition for informant/listening device being used in system phase? The ship who has the informant card, or the ship who has the listening device?

2) Cassian card says only "guess" and not "flip". Can you guess the already flipped dial from informant?

26 minutes ago, Minimono said:

Quoting the cards first for easy refferense:
Cassian: During the System Phase, you may choose 1 enemy ship at range 1-2 and guess aloud a bearing and speed, then look at that ship's dial. If the chosen ship's bearing and speed match your guess, you may set your dial to another maneuver.

INformant : Setup: After placing forces, choose 1 enemy ship and assign the Listening Device condition to it.

Listening Device: During the System Phase, if an enemy ship with the Informant upgrade is at range 0-2, flip your dial faceup.

1) When is the condition for informant/listening device being used in system phase? The ship who has the informant card, or the ship who has the listening device?

2) Cassian card says only "guess" and not "flip". Can you guess the already flipped dial from informant?

1. The ship with the condition assigned to it.

2. Yes he can.

2 hours ago, Minimono said:

Quoting the cards first for easy refferense:
Cassian: During the System Phase, you may choose 1 enemy ship at range 1-2 and guess aloud a bearing and speed, then look at that ship's dial. If the chosen ship's bearing and speed match your guess, you may set your dial to another maneuver.

INformant : Setup: After placing forces, choose 1 enemy ship and assign the Listening Device condition to it.

Listening Device: During the System Phase, if an enemy ship with the Informant upgrade is at range 0-2, flip your dial faceup.

1) When is the condition for informant/listening device being used in system phase? The ship who has the informant card, or the ship who has the listening device?

2) Cassian card says only "guess" and not "flip". Can you guess the already flipped dial from informant?

1. That's interesting, I'd never really thought about that. It'll be flipped up at the initiative of the ship with the Listening Device, I believe. The condition becomes an ability of the ship it's attached to, so if you place it on a high-initiative ship, you won't flip the dial until after all the lower-initiative ships in the lists have already "acted" in the Systems phase. Whisper with an Informant would have to make her decloaking choices before she'd force Wedge Antilles to flip his dial, for example.

2. I used to get into trouble in Math Class for something this when I was like 10. There'd be a problem "estimate the result of this sum" but I'd just solve the actual sum or product or whatever. I think there's a (very slim) linguistic argument that you could make that you cannot guess what you know to be true, but that's not the community consensus on how Cassian interacts with Listening Device (or Sense, for that matter). The consensus is that Cassian can guess exactly what's already been shown on the faceup dial.