What is the number of the model with three parallel printer ports?
{'header': ['Model number', 'Printer ports', 'Network ports', 'Network protocols', 'Firmware', 'Notes'], 'page_title': '', 'section_title': '', 'caption': '', 'rows': [['EX Plus', 'One Parallel', '10Base-2 and 10Base-T', 'TCP/IP, IPX/SPX, and DLC/LLC', 'Flash EEPROM', 'BOOTP & DHCP Client'], ['EX Plus3', 'Three Parallel', '10Base-2 and 10Base-T', 'TCP/IP, IPX/SPX, AppleTalk, and DLC/LLC', 'Flash EEPROM', 'DHCP Client (not BOOTP)'], ['170x', 'One Parallel ( IEEE 1284.4)', 'One RJ45 10Base-T Ethernet', 'TCP/IP, IPX/SPX, and DLC/LLC', 'Non-upgradeable', 'Discontinued'], ['175x', 'One USB 1.0', 'One RJ45 10/100Base-TX Ethernet', 'TCP/IP, AppleTalk, LPD (Windows and Mac OS only)', 'Non-upgradeable', 'Discontinued in favor of the en1700'], ['310x', 'One USB 1.0', 'One RJ45 10/100Base-TX Ethernet', 'TCP/IP, IPX/SPX, AppleTalk, and DLC/LLC', '2 MB', 'Discontinued in favor of the en3700']]}