HP part number cross reference?

Does anyone know of an online HP part number cross reference? I'm almost postive that I've seen one somewhere, but I can't find it now. I need to find the industry equivalents of the parts listed below. The 1810 prefix parts are probably just resistor packs (although the 16-pin ones could be RC networks or the like), the 1820 prefix parts are probably all 4000-series CMOS, and I'm guessing that the 1858 prefix part is an analog circuit. The T-28751 has a Motorola logo, but no other part number, not even an HP 4x4. I've occasionally seen other T-prefix parts in HP gear, but they seem fairly rare, and I'm not sure what the T signifies. I've tried HP PartSurfer, but it only listed one of the parts and didn't give any detail other than "MOS": http://outfield.external.hp.com/spi/ Thanks! Eric part # pins --------- ---- 1810-0252 9 SIP 1810-0316 16 1810-0319 16 1820-0927 16 1820-0936 14 1820-0938 16 1820-0939 14 1820-0941 16 1820-0946 14 1820-0949 14 1820-0970 16 1820-1114 16 1820-1145 16 1820-1241 16 1820-1408 14 1820-1466 16 1820-1485 16 1820-1514 16 1820-1578 16 1820-1665 16 1820-2037 14 1820-2080 16 1858-0038 14 T-28751 16