diff --git a/src/channel_codes.jl b/src/channel_codes.jl
index 03a36ba..501e9a8 100644
--- a/src/channel_codes.jl
+++ b/src/channel_codes.jl
@@ -1,12 +1,15 @@
 # Utilities for dealing with channel codes/trace IDs
 
 """
-    channel_code_parts(s) (net, sta, loc, cha)
+    channel_code_parts(s) -> (net, sta, loc, cha)
 
 Convert a single `String` `s` into its component SEED channel code parts.
 Returns a named tuple of network `net`, station `sta`, location `loc` and
 channel `cha`.  Empty components are given as empty `String`s.
 
+If the channel code does not appear to match any known pattern, `s` is
+returned in `sta` and all other parts are empty.
+
 This function assumes that `s` is an ASCII string, as per the SEED convention
 for channel IDs.
 
@@ -28,17 +31,20 @@ function channel_code_parts(s::String)
                 cha = join(parts[4:end])
             # Traditional SEED convention: NET_STA_LOC_CHA
             elseif nparts == 4
-                length(parts[1]) > 6 || error("unexpectedly short network name")
                 net = parts[1][1] == 'X' ? parts[1][7:end] : parts[1][6:end]
                 sta = parts[2]
                 loc = parts[3]
                 cha = parts[4]
             else
-                error("unexpected apparent XFDSN URN")
+                @warn("unexpected apparent XFDSN URN")
+                net = loc = cha = ""
+                sta = s
             end
         # Not really an XFDSN URN
         else
-            error("unexpectedly short channel id")
+            @warn("unexpectedly short channel id")
+            net = loc = cha = ""
+            sta = s
         end
 
     # Not an XFDSN URN but might have the same structure
@@ -57,10 +63,10 @@ function channel_code_parts(s::String)
             cha = join(parts[4:end])
         # Something else entirely: just put it all in sta
         else
-            net = nothing
+            net = ""
             sta = s
-            loc = nothing
-            cha = nothing
+            loc = ""
+            cha = ""
         end
     end
     (net=net, sta=sta, loc=loc, cha=cha)
diff --git a/test/channel_codes.jl b/test/channel_codes.jl
index 4a9ce12..26a04ef 100644
--- a/test/channel_codes.jl
+++ b/test/channel_codes.jl
@@ -5,33 +5,68 @@ using Test
 @testset "Channel codes" begin
     @testset "channel_code_parts" begin
         @testset "FDSN format" begin
-            # New format: separate channel code elements
-            @test LibMseed.channel_code_parts("XFDSN:AA_BB_CC_D_E_F") ==
-                (net="AA", sta="BB", loc="CC", cha="DEF")
-            @test LibMseed.channel_code_parts("FDSN:AA_BB_CC_D_E_F") ==
-                (net="AA", sta="BB", loc="CC", cha="DEF")
-            # Old format: single channel code
-            @test LibMseed.channel_code_parts("XFDSN:AA_BB_CC_DEF") ==
-                (net="AA", sta="BB", loc="CC", cha="DEF")
-            @test LibMseed.channel_code_parts("FDSN:AA_BB_CC_DEF") ==
-                (net="AA", sta="BB", loc="CC", cha="DEF")
-            # No _s
-            @test_throws ErrorException LibMseed.channel_code_parts("XFDSN:ldfjaldjjlfjk")
-            @test_throws ErrorException LibMseed.channel_code_parts("FDSN:ldfjaldjjlfjk")
-            # Too many parts
-            @test_throws ErrorException LibMseed.channel_code_parts("XFDSN:A_B_C_D_E_F_G")
-            @test_throws ErrorException LibMseed.channel_code_parts("FDSN:A_B_C_D_E_F_G")
-            # Not enough parts
-            @test_throws ErrorException LibMseed.channel_code_parts("XFDSN:A_B_C_D_E")
-            @test_throws ErrorException LibMseed.channel_code_parts("FDSN:A_B_C_D_E")
-            # Empty network code
-            @test LibMseed.channel_code_parts("FDSN:_BB_CC_D_E_F") ==
-                (net="", sta="BB", loc="CC", cha="DEF")
-            @test LibMseed.channel_code_parts("XFDSN:_BB_CC_D_E_F") ==
-                (net="", sta="BB", loc="CC", cha="DEF")
-            # 'Empty' everything
-            @test LibMseed.channel_code_parts("XFDSN:___ _ _ ") ==
-                (net="", sta="", loc="", cha="   ")
+            @testset "New format: separate channel code elements" begin
+                @test LibMseed.channel_code_parts("XFDSN:AA_BB_CC_D_E_F") ==
+                    (net="AA", sta="BB", loc="CC", cha="DEF")
+                @test LibMseed.channel_code_parts("FDSN:AA_BB_CC_D_E_F") ==
+                    (net="AA", sta="BB", loc="CC", cha="DEF")
+                # Old format: single channel code
+                @test LibMseed.channel_code_parts("XFDSN:AA_BB_CC_DEF") ==
+                    (net="AA", sta="BB", loc="CC", cha="DEF")
+                @test LibMseed.channel_code_parts("FDSN:AA_BB_CC_DEF") ==
+                    (net="AA", sta="BB", loc="CC", cha="DEF")
+            end
+
+            @testset "No _s" begin
+                @test (
+                    @test_logs (
+                        :warn, "unexpected apparent XFDSN URN"
+                    ) LibMseed.channel_code_parts("XFDSN:ldfjaldjjlfjk")
+                ) == (net="", sta="XFDSN:ldfjaldjjlfjk", loc="", cha="")
+                @test (
+                    @test_logs (
+                        :warn, "unexpected apparent XFDSN URN"
+                    ) LibMseed.channel_code_parts("FDSN:ldfjaldjjlfjk")
+                ) == (net="", sta="FDSN:ldfjaldjjlfjk", loc="", cha="")
+            end
+            
+            @testset "Too many parts" begin
+                @test (
+                    @test_logs (
+                        :warn, "unexpected apparent XFDSN URN"
+                    ) LibMseed.channel_code_parts("XFDSN:A_B_C_D_E_F_G")
+                ) == (net="", sta="XFDSN:A_B_C_D_E_F_G", loc="", cha="")
+                @test (
+                    @test_logs (
+                        :warn, "unexpected apparent XFDSN URN"
+                    ) LibMseed.channel_code_parts("FDSN:A_B_C_D_E_F_G")
+                ) == (net="", sta="FDSN:A_B_C_D_E_F_G", loc="", cha="")
+            end
+
+            @testset "Not enough parts" begin
+                @test (
+                    @test_logs (
+                        :warn, "unexpected apparent XFDSN URN"
+                    ) LibMseed.channel_code_parts("XFDSN:A_B_C_D_E")
+                ) == (net="", sta="XFDSN:A_B_C_D_E", loc="", cha="")
+                @test (
+                    @test_logs (
+                        :warn, "unexpected apparent XFDSN URN"
+                    ) LibMseed.channel_code_parts("FDSN:A_B_C_D_E")
+                ) == (net="", sta="FDSN:A_B_C_D_E", loc="", cha="")
+            end
+
+            @testset "Empty network code" begin
+                @test LibMseed.channel_code_parts("FDSN:_BB_CC_D_E_F") ==
+                    (net="", sta="BB", loc="CC", cha="DEF")
+                @test LibMseed.channel_code_parts("XFDSN:_BB_CC_D_E_F") ==
+                    (net="", sta="BB", loc="CC", cha="DEF")
+            end
+
+            @testset "'Empty' everything" begin
+                @test LibMseed.channel_code_parts("XFDSN:___ _ _ ") ==
+                    (net="", sta="", loc="", cha="   ")
+            end
         end
 
         @testset "_ separated" begin
@@ -45,7 +80,7 @@ using Test
 
         @testset "Other format" begin
             @test LibMseed.channel_code_parts("AABBCCDEF") ==
-                (net=nothing, sta="AABBCCDEF", loc=nothing, cha=nothing)
+                (net="", sta="AABBCCDEF", loc="", cha="")
         end
 
         @testset "MseedTraceID" begin