TROY Group MICR Basics Handbook - Manual (Page 8)

Section 1 Understanding MICR
MICR Basics Handbook -- Document #50-70300-001 Rev. C
1-4
Amount Field
The amount field occupies positions 1-12 on the MICR line. The amount field is not normally printed by
the check supplier. This field is used for processing the check and is coded after the check is drawn in the
post-encoding process at the bank of first deposit. From right to left, position 1 is the Amount symbol,
positions 2 and 3 are cents, positions 4-11 are dollars (leading zeros filled from the left) and position 12 is
the amount symbol. The amount field is designated as a fixed field that cannot be changed by the bank.
On-Us Field
The on-us field occupies positions 13-32 on the MICR line. Occupying nineteen spaces, each 1/8"
(0.125") wide and to the right of the transit field. This is not a fixed field and is normally used by the
bank for account number information, bank identification, check numbering or other special codes. An
on-us symbol must appear to the right of the last account number digit. The four characters to the right of
the on-us character (positions 13-16) are for special bank use.
Transit Field
The transit field is sometimes referred to as the routing field and occupies positions 33-43 on the MICR
line. The routing field is reserved for the combined transit and routing codes used to direct the check as it
passes through the system. This code is also referred to as the bank code. Because the numbers in this
field are specially assigned, the transit field is designated as a fixed field that cannot be changed by the
bank.
Referring back to Figure 1-4 on the previous page, position 33 is the transit symbol, position 34 is the
check digit, position 35-38 is the bank number, position 39-42 is the routing number, and position 43 is
the transit symbol.
EPC (External Processing Field)
The field immediately to the right of the auxiliary on-us field is a one-digit field called the EPC (External
Processing Code) field. The field is either, but not both, positions 44 or 45 of the MICR line. This field
is strictly controlled by the ASC (Accredited Standards Committee) X9B. It is used for specific purposes.
The EPC field cannot be used without written authorization from the ASC X9B.
Auxiliary On-Us Field
The auxiliary on-us field occupies positions 45 and on up to any number of digits that fit the size of the
check (digits may not extend further than 1/8” from the edge of the check) on the MICR line. The limits
on the number of digits in this field are dictated by the length of the check and programming requirements
of check-printing software packages.
The auxiliary on-us field is not present on small format checks (e.g., 6" personal style checks) as it would
extend past the end of the check. On larger format business checks, this field is allowed to the left of the
transit number field. The auxiliary on-us field usually contains the check serial number, and it may also
contain accounting control information specific to that account.
The characters in this field are usually the MICR consecutive numbering of the checks. The characters
here must always be immediately preceded by and followed by an on-us symbol.