Toshiba RSTU2 Card (Refurbished)This card is an 8 circuit standard telephone interface unit with message waiting. It provides 8 standard telephone station ports. More Information 1 port per DTMF or rotary telephone, or peripheral device such as voicemail, autoattendant, fax, etc 1 port per off premises station, type OL13B line The RSTU2 works on the Toshiba DK40i Expansion, DK424 and DK424i systems.