В некоторых чеках нет фразы Entry Method, но рядом с номером карты указано C.
У меня есть предположение, что C означает, что это кредитная карта

Хотелось бы знать, что означает Entry Method

Payments are entered in groups. Groups of associated payments are called batches. For example, you can create batches for:

Payments entered by a cashier on a specific date
A group of payments for a particular payment type
A tape of payments taken by a payment processing service
You can create payment batches for whatever type or grouping of payments you choose. In order to control balancing, SunGard Public Sector recommends that cashiers open new batches every day. Each cashier can create up to 100 batches per day (batch numbers 0-99).

When you open a new batch, CR automatically assigns a status of "O" for "Open" to the batch. The status of the batch does not change until you change it to "C" for "Closed."
Источник:
http://www.venicegov.com/Files/Employee_Corner/HTE_Help/Cash_receipts/Content/NaviLine/PaymentProcessing/overview_of_payment_processing.htm#D50Q4B

C - мммм, может быть chip или contactless....

Card Entry Method
Must appear immediately after the reference number as a single letter identifier for card entry. Note that the full word (e.g., “Swiped” or “Tapped”) must not be used. Only the single letter abbreviation is acceptable:

S Swiped
card is swiped, and transaction is not EMV fallback

M Manually Entered
card is manually keyed, and transaction is not EMV fallback

C Chip Card Reader
card is inserted, and transaction completes an approved or declined EMV transaction or non-EMV transaction using EMV functionality

T Tapped
Card/NFC device is tapped, and transaction is MSD

H Tapped
Card/NFC device is tapped, and transaction is EMV

F Fallback Swiped
EMV contact-based chip card is swiped at the fallback prompt, and the transaction completes an approved or declined fallback transaction

G Fallback Manually Entered
EMV contact-based chip card is manually entered at the fallback prompt the transaction completes an approved or declined fallback transaction