This is one of four different variants of line card from the System X exchange. This particular card is known as the "one o four o two" on account of its product part number. The above card was only ever manufactured at Edge Lane in Liverpool and this particular card was in service with British Telecom for over 21 years before becoming BER (Beyond Economical Repair) in Q2 of 2011 through water damage. It was subsequently scrapped. Although difficult to see in this picture there are components missing from the card that have been used to repair other cards.
Function: Line card.
Product code: K10402ACP
Manufacture date: 1990 Week 36.