From SEI: CMMI Models FAQ:
EIA 731, the Systems Engineering Capability Model, is a source document for CMMI. A mapping that compares EIA 731 and CMMI v1.1 is available on the SEI Web site, including a mapping from CMMI v1.1 to EIA 731 at http://www.sei.cmu.edu/cmmi/casestudies/mappings/cmmimappings.cfm, from EIA 731 to CMMI v1.1 available at http://www.sei.cmu.edu/cmmi/casestudies/mappings/cmmimappings.cfm, and a document to help you interpret these mappings at http://www.sei.cmu.edu/cmmi/casestudies/mappings/cmmimappings.cfm. An article that discusses Transitioning from EIA/IS 731 to CMMI is also available at
https://theqalead.com/topics/what-happened-to-crosstalk-journal-of-defe…
ITAA EIA-731-1 was formerly EIA/IS 731.1.