Bulgaria 10 Lev 1987 field trial. PKM-261/87 Three digit number.
possible serial range
351-500 (150 pieces issued)? probably also exists without serial number, though we need a copy for the museum.
In 1981 Bulgarian Ministry of Telecommunications began to form a business arrangement with Alcatel to supply magnetic Phonecard operated public telephones. The Telecom authority wanted to produce the magnetic cards themselves and set up limited trials of locally produced phonecards of two main types, white and black. A white card series are compressed card, and the black series are plastic. The magnetic bands are of ISO123 standard.
The quality and performance of the cards proved to be not of a standard needed for a national phonecard payphone roll-out, so in 1985, the ministry began testing magnetic cards produced by ZIMEX in Eastern Germany.
A small scale trial followed in 1987 with 3 digit serial cards (PKM-261/87 meaning 1987 dated on reverse), with the same 4 card values as the 1982 trials, and National roll-out in 1988, with the same easily recognizable public issue of 1988.(88 dated on reverse)
1987 serial ranges estimated
001-100 -1 Lev Green
101-200 -2 Lev Orange
201-350 -5 Lev Blue
351-500 -10 Lev Yellow