Signals, Calls, and Marches has a notably "cleaner" sound in comparison to the band live performances and subsequent recordings, which Marc Masters of Pitchfork called "somewhat misrepresentative" of the band, as "Harte's production cleaned up the band's brutally loud live sound." Guitarist Roger Miller noted that the sound probably helped the band become more accessible, recalling:
We played a show in Cleveland ('81 or '82) and we were on the street in front of the club. A girl came up to us and said how much she was looking forward to the show, and that she loved "That's When I Reach for My Revolver". We thought we were golden. However, once we started playing, people backed up against the wall and after the first song did not applaud or respond to us one bit, even after we started heckling them. Even when we played "Revolver". So, it is quite probably true that the "mild-mannered" recording we made on Signals reached more people than if we recorded it in a more furious or noisy fashion.
Signals, Calls, and Marches was released on July 4, 1981 by record label Ace of Hearts.
For the CD reissue, Rykodisc remastered the six original songs and added the two tracks from the band's 1980 debut 7" single, "Academy Fight Song". The EP was remastered by Matador Records in 2008 with video material and extra tracks.
Signals, Calls, and Marches has been well-received by critics.
In his retrospective review, Mark Deming of AllMusic wrote, "if Mission of Burma were not yet at the peak of their form, most bands blazing as many trails as this one did lost their footing a lot more often that Burma did on these six songs; Signals, Calls and Marches was as accomplished and impressive a debut as any American band would release in the 1980s." Marc Masters of Pitchfork called it "impeccable" and "probably the best Mission of Burma release ever.". Pitchfork would also go on to rank it the 53rd greatest album of the 80s, despite being an EP.
Signals, Calls, and Marches is considered an immensely influential landmark in the field of indie rock and alternative rock. Mark Deming of AllMusic wrote, "One could argue that [Signals, Calls, and Marches] was the point where indie rock as a separate and distinct musical subgenre well and truly began. Mission of Burma's music had the brawn and the volume of hardcore punk, but with a lyrical intelligence and obvious musical sophistication that set them apart from the Southern California faster-and-louder brigade." Marc Masters Pitchfork opined that the EP "reverberated loudly through alternative rock for three decades, influencing everyone from R.E.M. to Fugazi to Nirvana."