Is the Stargate half duplex or one way? I know it can send radio signals both ways but doesn’t seem like it can send and receive matter. It seems only the dialer can transfer matter.

In “The Fifth Race” Gen Hammond he gives this impression. Season 2 Episode 15 -22:00.

  • 1
    Does anyone want to mention the implications on the original cut of the pilot 😬
    – Crazy Dino
    Apr 8, 2021 at 14:11
  • Something is missing in that final paragraph. Apr 8, 2021 at 15:09
  • 1
    And how many stop bits and parity bits are used?
    – Jon Custer
    Apr 8, 2021 at 16:07
  • The gate goes both ways. How else could the team return?
    – NomadMaker
    Apr 8, 2021 at 17:04
  • Related: scifi.stackexchange.com/q/2943/13875 Apr 8, 2021 at 18:42

1 Answer 1


It is stated on multiple occasions that wormhole travel is uni-directional for normal matter. There are exceptions for radio waves which can travel freely in both directions, allowing the SGC to communicate with their offworld teams.

CARTER: Well, even though the wormhole only allows matter to travel one way we are able to transmit radio signals back and forth.

SG1: Watergate

Various other electro-magnetic phenomena can also travel through an outgoing wormhole back to its source.

McKAY: No, you're both horribly wrong, both of you, but you gave me an idea. We know that certain waves can travel in both directions through a wormhole. Uh, radio signals, for one...We send a massive EM pulse back through the wormhole, knock out whatever it is that's making this happen on the other end.

SG1: Redemption, Part 2

As can intense gravity fields.

SIMMONS: It's an outgoing wormhole. Nothing can come through this way.

CARTER: Except for the black hole's gravity. Now close it! That's an order!

SG1: A Matter of Time

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