If you have a voice modem installed in your pc, you can use it to for call recording.
Connect your telephone to your modem, dial the number as usually and pressing the record button, whole conversation will be saved to your hard disk.
You can set it in auto recording mode where all of your incoming calls will be recorded automatically with no intervention.
You can select the voice compression your modem supports, such as PCM-8bit, PCM-16bit, unsigned PCM-8bit, u-law, a-law, IMA ADPCM, 4-ADPCM
You can select the compression format of the wav files saved to your hard disk, such as uncompressed PCM, ACELP, a-law, u-law, DSP truespeech, GSM 6.10, IMA ADPCM, Microsoft ADPCM, G723.1, WMA, VOX, BTV digital, Creative fastspeech, MP3 and many others your system supports. Selecting the right format you can have compression ratio about 2.81Mb/hour.
More : Download Advanced Phone Recorder v1.7.8