diff --git a/src/data/byte_str.rs b/src/data/byte_str.rs
index f8d3972..2435e81 100644
--- a/src/data/byte_str.rs
+++ b/src/data/byte_str.rs
@@ -221,7 +221,7 @@ impl Display for ByteStr {
             let mut ctl = false;
             for c in s.chars() {
                 let v = c as u32;
-                if (c.is_control() && v != 0x20) || v < 0x20 || v >= 0x7F {
+                if (c.is_control() && v != 0x20) || !(0x20..0x7F).contains(&v) {
                     if !ctl {
                         ctl = true;
                     }
@@ -282,6 +282,7 @@ mod _serde {
     use std::convert::TryFrom;
     use std::ops::Deref;
 
+    use amplify::hex::{FromHex, ToHex};
     use serde_crate::de::Error;
     use serde_crate::{Deserialize, Deserializer, Serialize, Serializer};
 
@@ -292,7 +293,11 @@ mod _serde {
         where
             S: Serializer,
         {
-            self.as_ref().serialize(serializer)
+            if serializer.is_human_readable() {
+                self.as_ref().to_hex().serialize(serializer)
+            } else {
+                self.as_ref().serialize(serializer)
+            }
         }
     }
 
@@ -301,7 +306,12 @@ mod _serde {
         where
             D: Deserializer<'de>,
         {
-            let vec = Vec::<u8>::deserialize(deserializer)?;
+            let vec = if deserializer.is_human_readable() {
+                let hex = String::deserialize(deserializer)?;
+                Vec::<u8>::from_hex(&hex).map_err(D::Error::custom)?
+            } else {
+                Vec::<u8>::deserialize(deserializer)?
+            };
             ByteStr::try_from(vec.deref())
                 .map_err(|_| D::Error::invalid_length(vec.len(), &"max u16::MAX bytes"))
         }