Ask which company performs each role for your actual account. A familiar logo or terminal does not identify the underwriter or the bank moving the funds.
01Acquirer, processor, and sponsor bank
An acquirer or acquiring program contracts for card acceptance; processors provide transaction technology; a sponsor bank supplies regulated banking participation where required. The exact relationships are set in provider agreements.
02MID, TPN, gateway, and POS
A merchant ID identifies an account within a provider setup. A terminal profile identifies device configuration. A gateway sends authorized payment messages. A POS manages the sale and may connect to the payment system.
03ACH, returns, reserves, and settlement
ACH refers to bank-account transfers. A return is a bank payment sent back under applicable rules. A reserve holds funds under contract terms. Settlement is the provider-controlled movement of proceeds according to the merchant agreement.