HOUSTON, TEXAS – March 10, 2007 -Enterprise Systems Corporation announced today that Marathon Oil Company has selected Enterprise Systems to perform an extensive CS1000 IP Telephony deployment at its facilities in Equatorial Guinea. The scope of work will include installation of a CS1000 system with IP trunking and satellite networking. Enterprise Systems was chosen by Marathon after extensive evaluation of different Nortel Partners. A proven track record, extensive off-shore experience and reputation contributed to the decision.