diff --git a/man3/termios.3 b/man3/termios.3
index 4fbd34a52..8c88c25e4 100644
--- a/man3/termios.3
+++ b/man3/termios.3
@@ -953,6 +953,24 @@ to by \fItermios_p\fP to \fIspeed\fP, which must be one of these constants:
 	B1152000
 	B1500000
 	B2000000
+.ft P
+.fi
+.PP
+These constants are additionally supported on the SPARC architecture:
+.PP
+.nf
+.ft B
+	B76800
+	B153600
+	B307200
+	B614400
+.ft P
+.fi
+.PP
+These constants are additionally supported on non-SPARC architectures:
+.PP
+.nf
+.ft B
 	B2500000
 	B3000000
 	B3500000
@@ -960,6 +978,11 @@ to by \fItermios_p\fP to \fIspeed\fP, which must be one of these constants:
 .ft P
 .fi
 .PP
+Due to differences between architectures, portable applications should check
+if a particular
+.BI B nnn
+constant is defined prior to using it.
+.PP
 The zero baud rate,
 .BR B0 ,
 is used to terminate the connection.