Clipper is a MIFARE DESFire based public transit ticketing system in use by multiple agencies in San Francisco (and the greater Bay Area), CA, USA.

The system was originally developed as TransLink by ERG and Motorola (many fareboxes in use bare ERG logos), but since launch is administered by Cubic (value-add machines are of a standard Cubic design, similar to those in Los Angeles and Brisbane).

Clipper uses a different card format to other Cubic and ERG systems.

All values on the card are big-endian, and timestamps are stored as seconds since 1900-01-01 00:00:00 UTC.

All data is in application ID 0x9011f2.

Support for this card was mostly inherited from Farebot. Compatibility with original TransLink cards is unknown. Travel passes are not yet supported.

File 0x1 (Card Metadata)

First	Last	Length	Field description
8	9	2	Card expiry date, in days since 1900-01-01

File 0x2 (Balance)

First	Last	Length	Field description
4	7	4	Last use timestamp
18	19	2	Card balance (cents)

File 0x4 (Refills)

Refill records are 32 bytes long. Each record has the following format:

First	Last	Length	Field description
2	3	2	Transit agency
4	7	4	Timestamp
8	11	4	Machine ID (on receipts, this is shown in hex)
14	15	2	Refill amount (in cents)

File 0x5

Probably a pointers file

File 0x6

Probably a pointers file

File 0x8

First	Last	Length	Field description
0	0	1	Const 0x1
1	4	4	Serial
5	5	1	Const 0x1
6	7	2	Zero-filled
8	8	1	Const 0xf (Ticket type?)
9	31	23	Zero-filled

File 0xe (Trips)

Trip records are 32 bytes long.

Each trip contains 1 or 2 records corresponding to it -- one which has only an entry timestamp and station ID, but may also have one with an exit timestamp and station ID. Only certain transit modes require "tapping off" when exiting a station (eg: Caltrain).

Each record has the following format:

First	Last	Length	Field description
1	1	1	Transfer counter
2	3	2	Transit agency
4	2	2	Something about transfers
6	7	2	Fare (in cents)
8	9	2	Pointer to validation/subscription
10	11	2	Vehicle number
12	15	4	Entry timestamp
16	19	4	Exit timestamp (optional)
20	21	2	Entry station ID
22	23	2	Exit station ID (optional)
28	29	2	Route ID
30	31	2	Transport code

File 0xf (Validations and subscriptions and partial trips)

Validation records are 32 bytes long.

Bytes 2 and 3 determine the format

Format 7000:

First	Last	Length	Field description
0	1	2	2000 (tag-on) or 20f0 (tag-off)
2	3	2	7000
4	5	2	date + 1806 days = almost 5 years (some kind of expiry?), in days since 1900-01-01
6	7	2	ff-filled
8	11	4	Entry timestamp
12	13	2	Entry station ID
14	31	18	ff-filled

Format 8000:

First	Last	Length	Field description
0	1	2	2000
2	3	2	3000
4	5	2	Some date in the future, in days since 1900-01-01
14	15	2	Some date in the past, in days since 1900-01-01

BART station assignment

It looks like the numbers were first assigned on year 2000 map of BART.

See https://commons.wikimedia.org/wiki/File:Revised_BART_map.svg

It starts with Colma and follows Yellow line to Pittsburg

Number	Station
0x01	Colma
0x02	Daly City
0x03	Balboa Park
0x04	Glen Park
0x05	24st/Mission
0x06	16st/Mission
0x07	Civic Center
0x08	Powell St.
0x09	Montgomerry
0x0a	Embarcadero
0x0b	West Oakland
0x0c	12st/Oakland city center
0x0d	19st/Oakland
0x0e	MacArthur
0x0f	Rockridge
0x10	Orinda
0x11	Lafayette
0x12	Walnut Creek
0x13	Pleasant Hill
0x14	Concord
0x15	North Concord/Martinez
0x16	Pittsburg/Bay Point

0x10 and 0x16 are unconfirmed

Then it continues at branching point of orange/red line from yellow line (Ashby) and continues to Richmond

Number	Station
0x17	Ashby
0x18	Downtown Berkeley
0x19	North Berkeley
0x1a	El Cerrito Plaza
0x1b	El Cerrito del Norte
0x1c	Richmond

Then it continues at branching point of orange/green line from yellow line (Lake Meritt) and continues to Fremont.

Number	Station
0x1d	Lake Meritt
0x1e	Fruitvale
0x1f	Coliseum
0x20	San Leandro
0x21	Bay Fair
0x22	Hayward
0x23	South Hayward
0x24	Union City
0x25	Fremont

However our database doesn't match it on 0x20 and 0x21 - likely an error in database

Then it logically should continue with blue line to Dublin/Pleasanton

Number	Station
0x26	Castro Valley
0x27	Dublin/Pleasanton

However our database doesn't match it on 0x26 - likely an error in database Then it goes on to the other direction from Colma station following yellow line to SFO

Number	Station
0x28	South San Francisco
0x29	San Bruno
0x2a	San Francisco International airport

Then it goes on to blue/red line branching:

Number	Station
0x2b	Millbrae

Then it follows newer station added as they were constructed:

Number	Station
0x2c	West Dublin/Pleasanton (February 2011)
0x2d	Oakland airport station (November 2014)
0x2e	Warm Springs/South Fremont (March 2017)
0x2f	Pittsburg Center (May 2018)
0x30	Antioch (May 2018)

However 0x2e, 0x2f and 0x30 are unconfirmed

Single-trip

Single-trips are per-agency. Most buses give at most a paper receipt. BART, Caltrain and VTA use magnetic card for single trip. So far the only NFC single-ride ticket are Muni's and GGF's "Paper Clipper" on Mifare Ultralight. Its format is a mixture between Clipper and Cubic MFU structures.

General structure

Page	Purpose
0-2	Manufacturer data
3	Serial-number, big endian
4-5	Header
6-10	Transaction 1
11-15	Transaction 2

Header

All offsets are in bits, big-endian

First	Length	Last	Value
0	8	7	Always 0x13
8	8	15	Ticket type
16	16	31	??
32	16	47	Product code
48	16	63	Base/Expiry date, in days since 1990

Transaction

All offsets are in bits, big-endian

First	Length	Last	Value
0	7	6	Transaction counter
7	17	23	Transaction type
24	17	40	Transaction time, in minutes before base day
41	17	57	Station ID
58	10	67	???
68	5	73	Agency ID
74	6	79	???
80	4	83	Balance sequence counter
84	6	89	Number of remaining trips
90	10	99	???
100	10	109	Transfer expiry timestamp
110	18	127	???
128	32	159	Hash