Other Networks

Support for American Express, Discover, JCB, and UnionPay.

American Express (AMEX)

Detection

PAN prefix: 34, 37
15 digits

from iso8583sim.core.types import detect_network, CardNetwork

network = detect_network("378282246310005")
assert network == CardNetwork.AMEX

Required Fields

Field	Name	Format
2	PAN	LLVAR (15 digits)
3	Processing Code	n6
4	Amount	n12
11	STAN	n6
22	POS Entry Mode	n3
25	POS Condition Code	n2

Example

from iso8583sim.core.types import ISO8583Message, CardNetwork

message = ISO8583Message(
    mti="0100",
    network=CardNetwork.AMEX,
    fields={
        0: "0100",
        2: "378282246310005",       # AMEX PAN (15 digits)
        3: "000000",
        4: "000000010000",
        11: "123456",
        22: "051",
        25: "00",
        41: "TERM0001",
        42: "MERCHANT123456 ",
    }
)

AMEX-Specific Notes

Uses 15-digit PANs (not 16)
Different response code meanings for some codes
CVV location differs (4 digits on front)

Discover

Detection

PAN prefix: 6011, 644-649, 65
16-19 digits

network = detect_network("6011111111111117")
assert network == CardNetwork.DISCOVER

Required Fields

Field	Name	Format
2	PAN	LLVAR (16-19 digits)
3	Processing Code	n6
4	Amount	n12
11	STAN	n6
22	POS Entry Mode	n3

Example

message = ISO8583Message(
    mti="0100",
    network=CardNetwork.DISCOVER,
    fields={
        0: "0100",
        2: "6011111111111117",      # Discover PAN
        3: "000000",
        4: "000000010000",
        11: "123456",
        22: "051",
        41: "TERM0001",
        42: "MERCHANT123456 ",
    }
)

Discover-Specific Notes

D-PAS for tokenization
Similar authorization flow to VISA
ProtectBuy for 3D Secure

JCB

Detection

PAN prefix: 3528-3589
16-19 digits

network = detect_network("3530111333300000")
assert network == CardNetwork.JCB

Required Fields

Field	Name	Format
2	PAN	LLVAR (16-19 digits)
3	Processing Code	n6
4	Amount	n12
11	STAN	n6
22	POS Entry Mode	n3
25	POS Condition Code	n2

Example

message = ISO8583Message(
    mti="0100",
    network=CardNetwork.JCB,
    fields={
        0: "0100",
        2: "3530111333300000",      # JCB PAN
        3: "000000",
        4: "000000010000",
        11: "123456",
        22: "051",
        25: "00",
        41: "TERM0001",
        42: "MERCHANT123456 ",
    }
)

JCB-Specific Notes

Japan-based network with global acceptance
J/Secure for 3D Secure authentication
Currency conversion considerations for international transactions

UnionPay

Detection

PAN prefix: 62
16-19 digits

network = detect_network("6200000000000005")
assert network == CardNetwork.UNIONPAY

Required Fields

Field	Name	Format
2	PAN	LLVAR (16-19 digits)
3	Processing Code	n6
4	Amount	n12
11	STAN	n6
22	POS Entry Mode	n3
25	POS Condition Code	n2
49	Currency Code	n3

Note: UnionPay requires Field 49 (Currency Code).

Example

message = ISO8583Message(
    mti="0100",
    network=CardNetwork.UNIONPAY,
    fields={
        0: "0100",
        2: "6200000000000005",      # UnionPay PAN
        3: "000000",
        4: "000000010000",
        11: "123456",
        22: "051",
        25: "00",
        41: "TERM0001",
        42: "MERCHANT123456 ",
        49: "156",                  # CNY (Chinese Yuan)
    }
)

UnionPay-Specific Notes

China-based network
Field 49 required for currency identification
QuickPass for contactless payments
Supports both debit and credit products

Response Codes Comparison

Code	AMEX	Discover	JCB	UnionPay
00	Approved	Approved	Approved	Approved
05	Do Not Honor	Do Not Honor	Do Not Honor	Do Not Honor
14	Invalid Card	Invalid Card	Invalid Card	Invalid Card
51	Insufficient Funds	Insufficient Funds	Insufficient Funds	Insufficient Funds
54	Expired Card	Expired Card	Expired Card	Expired Card

Adding Custom Network Support

To add a new network:

# 1. Add to CardNetwork enum
class CardNetwork(Enum):
    NEW_NETWORK = "NEW_NETWORK"

# 2. Add detection rule
def detect_network(pan: str) -> CardNetwork | None:
    if pan.startswith("999"):  # Example prefix
        return CardNetwork.NEW_NETWORK
    # ... existing rules

# 3. Add field definitions
NETWORK_SPECIFIC_FIELDS[CardNetwork.NEW_NETWORK] = {
    62: FieldDefinition(...),
}

# 4. Add required fields
NETWORK_REQUIRED_FIELDS[CardNetwork.NEW_NETWORK] = [2, 3, 4, 11]