The Josephson array voltage standards (JVSs) of the VNIIM and the PTB were compared using a new portable JVS (PJVS) as travelling standard. The PJVS which uses a 1 V programmable superconductive–insulator–normal–insulator–superconductive Josephson array is described in detail. The results of the comparison show that the new PJVS is suitable for comparisons and verifications of laboratory JVS with an uncertainty of less than 1×10−9.