WAN and VOICE on the same E1 Circuit

hi there is it possible to split  one E1 circuit for data and voice.  Basicly we have one HDSL E1 circuit and we would like to use it for WAN but the also to use it to route PSTN calls. does anybody done that before. Solution: WAN and VOICE on the same E1 Circuit http://www.cisco.com/en/US/docs/ios/12_3/vvf_c/voice_port_configuration_guide/ch3_dgtl.html http://www.cisco.com/en/US/docs/ios/12_1/termserv/configuration/guide/dcdchant.html#wp1001062