Consul
Models and s/n	Y	M	D	Remarks	Ref.
Portable
	up to 1960			The serial numbers from the Remington license models before 1960 seem to have the prefix "ZP"	12
#MM(M)ssssss	from 1960			The first digit of serial number indicates the year of production (4 means 1964), followed by model number (2 or 3 digits), followed by the machine's s/n of 6 digits	12
For further information please look at Will Davis' Portable Typewriter page : http://www.hometown.aol.com/page3.html