Firmware revisions through 1.620 use RPI
Firmware revisions from 1.628 use RPI+
Check the response to "ATI3" for firmware info.
Note: Some older ACF modems can operate in either RPI+ or the traditional hardware ECC mode.
RC144ATFD-x US/Canada RC144ATF-x US/Canada RCV144ATF-x US/Canada RC144ATFWD-x + 128k-byte External ROM Multicountry RC144ATFW-x + 128k-byte External ROM Multicountry RCV144ATFW-x + 128k-byte External ROM Multicountry RC144ATFWD-x + 8k-byte External ROM Single country RC144ATFW-x + 8k-byte External ROM Single country RCV144ATFW-x + 8k-byte External ROM Single country Notes: Model options: x Host/DTE interface (P = Parallel host; S = Serial DTE) D Data only (no fax). V Voice (including business audio for parallel interface) W World class support.