openssl pkcs12 -in domain.pfx -clcerts -nokeys -out domain.cer
openssl pkcs12 -in domain.pfx -nocerts -nodes -out domain.key
For Audiocodes:
openssl pkcs12 -in domain.pfx -clcerts -nokeys -out domain.cer
rename domain.cer to domain.pem
openssl pkcs12 -in domain.pfx -nocerts -nodes -out domain.key
rename domain.key to domain-key.pem