diff --git a/contrib/groff/eqn/neqn.sh b/contrib/groff/eqn/neqn.sh
index 770376732b29..cc32e66406b3 100644
--- a/contrib/groff/eqn/neqn.sh
+++ b/contrib/groff/eqn/neqn.sh
@@ -2,4 +2,19 @@
 # Provision of this shell script should not be taken to imply that use of
 # GNU eqn with groff -Tascii|-Tlatin1 is supported.
 
-exec @g@eqn -Tascii ${1+"$@"}
+# Default device.
+if test `expr "$LC_CTYPE" : ".*\.ISO_8859-1"` -gt 0 || \
+   test `expr "$LANG" : ".*\.ISO_8859-1"` -gt 0
+then
+	T=-Tlatin1
+else
+if test `expr "$LC_CTYPE" : ".*\.KOI8-R"` -gt 0 || \
+   test `expr "$LANG" : ".*\.KOI8-R"` -gt 0
+then
+	T=-Tkoi8-r
+else
+	T=-Tascii
+fi
+fi
+
+exec @g@eqn -T${T} ${1+"$@"}
diff --git a/contrib/groff/src/preproc/eqn/neqn.sh b/contrib/groff/src/preproc/eqn/neqn.sh
index 770376732b29..cc32e66406b3 100644
--- a/contrib/groff/src/preproc/eqn/neqn.sh
+++ b/contrib/groff/src/preproc/eqn/neqn.sh
@@ -2,4 +2,19 @@
 # Provision of this shell script should not be taken to imply that use of
 # GNU eqn with groff -Tascii|-Tlatin1 is supported.
 
-exec @g@eqn -Tascii ${1+"$@"}
+# Default device.
+if test `expr "$LC_CTYPE" : ".*\.ISO_8859-1"` -gt 0 || \
+   test `expr "$LANG" : ".*\.ISO_8859-1"` -gt 0
+then
+	T=-Tlatin1
+else
+if test `expr "$LC_CTYPE" : ".*\.KOI8-R"` -gt 0 || \
+   test `expr "$LANG" : ".*\.KOI8-R"` -gt 0
+then
+	T=-Tkoi8-r
+else
+	T=-Tascii
+fi
+fi
+
+exec @g@eqn -T${T} ${1+"$@"}