MIL-S-55562C, MILITARY SPECIFICATION, SHOP, ELECTRONIC, SEMITRAILER MOUNTED AN/ARM-189( ) AND AN/ASM-190 (31 MAR 1980)., This specification covers the modification of Semi-Trailers, Vans, Electronic, M373A2 and the installation of the applicable equipment and ancillary items into the modified vans to form Electronic Shops, Semi-Trailer Mounted, AN/ASM-189( ) and AN/ASM-190 ( ). (See 6.5)