In the stationary business, there is the terminal ID, the CC number and the customer number.
The terminal ID refers purely to a card terminal, it is device-related. You will find this number on every receipt printout and usually on a sticker on your device. If you have several devices in use, you will have several terminal IDs.
The VU number (contract company number) is a unique identification number for a company in a contract. You can find this number on your credit card statement or on your transaction statement.
The customer number is a unique identification number for customers in an accounting system. You can find this number on the monthly statement from the card terminal.