diff --git a/src/system/ether.1 b/src/system/ether.1
index ba0d7b04..28f1b8d8 100644
--- a/src/system/ether.1
+++ b/src/system/ether.1
@@ -81,6 +81,8 @@
 
 EBLK
 
+IFE IMPP, IMPUP:	0	;If no IMP, provide this variable for TELNET etc.
+
 ETHME:	BLOCK %NEAT"WORDS	;Our MAC address, as ARP table entry
 				;(device driver must initialise this)