Model 53E is a special designation for Models 520 and 52H converted to 53H functionality (33 MHz Processor and 33 MHz memory) as on-site upgrade. See US Announcement Letter 192-005Archivado el 7 de octubre de 2012 en Wayback Machine.
Model 58F is a special designation for Models 530H, 550 and 560 converted to Model 580 functionality (62.5 MHz Processor) as on-site upgrade. See US Announcement Letter C92-016Archivado el 7 de octubre de 2012 en Wayback Machine.
Model 53E is a special designation for Models 520 and 52H converted to 53H functionality (33 MHz Processor and 33 MHz memory) as on-site upgrade. See US Announcement Letter 192-005Archivado el 7 de octubre de 2012 en Wayback Machine.
Model 58F is a special designation for Models 530H, 550 and 560 converted to Model 580 functionality (62.5 MHz Processor) as on-site upgrade. See US Announcement Letter C92-016Archivado el 7 de octubre de 2012 en Wayback Machine.