Do you remember Carrier Access Corp? They used to design and manufacture optical transport equipment. Even though their platforms are manufacturing discontinued, there is still a demand for certain boards. Many large service providers still have pockets of the equipment installed.
Let us know at TruePulse if you need any replacement Carrier Access boards. For example, we still have an OCU-DP available, part number 740-0067, HECI code SIIXA3DDAA.