Morsa publishes this guide. Morsa is software with an AI agent that works in your ERP, email and Teams; it enters incoming POs and works out each line’s answer, and a person approves the 855.
Quick answer
The deadline: set by your customer, not by X12. Dot Foods wants the first 855 within 24 hours, Gentex within 12 hours for North American suppliers [1][2].
The clock starts when the 850 reaches you, not when someone opens it [1][2]; weekends and slow mailbox checks count.
First 855 fast, then the update: confirm what you can at once, then follow the customer’s rule for changes, which differs by customer (below).
A 997 is not an 855. The 997 only says a file arrived and parsed; the 855 is sent in addition [4]. The order and line codes are in the two tables below.
When the 855 is due, and what starts the clock
Customer | Rule |
|---|---|
Dot Foods (food distributor) | First 855 within 24 hours of receiving the PO [1] |
Gentex (automotive supplier, as buyer) | 12 hours for North American suppliers, 24 hours outside North America, 60 minutes when your lead time to Gentex is under 24 hours [2] |
Other customers range from 12 hours to 48; SPS Commerce, an EDI provider, says 24 to 48 is common [3].
Both guides count from receipt of the 850 [1][2], and neither stops the clock for weekends; Gentex says you may send 855s “at anytime including holidays and weekends” [2]. An 850 that lands Friday at 6 p.m. can be due Saturday morning. If your EDI software checks the mailbox every four hours, that wait comes out of your 12; set the pickup to every few minutes, or have the provider alert someone when an 850 lands.
Sending a compliant 855 from your ERP
Get the customer’s 855 guide and note the X12 version, required segments, accepted codes, change rule and test IDs. Dot Foods, for example, accepts only AC and AD at order level [1].
Pick how the 855 is built. With integrated EDI, the 850 becomes a sales order in your ERP (NetSuite, Business Central, Epicor, Infor, SAP Business One or another) and the 855 is built from it; a full-service provider such as SPS Commerce writes and maintains the map to each customer’s spec [3]. With web EDI, someone types the 855 into a browser portal. Prices for both are in what EDI costs.
Trigger it on order entry, not shipment. The 855 goes out when the sales order is saved with a promise date on each line.
Echo the 850 exactly. BAK03 carries the customer’s PO number as received, with no prefix or suffix, because it is what their system matches on [5]. Return the PO1 line numbers and part numbers as sent, and the ship-from or supplier site in N1 where the guide asks for it; Gentex does [2].
Test before go-live. Send test 855s with ISA15 set to T (test); the customer checks them against its guide and switches you to P (production). Polaris uses this split and returns a 997 for every file [6].
The fast first 855, then the update
Send what you know within the window:
Lines you can ship as ordered: IA, with the ship date.
Lines short on stock: IQ for the quantity you can ship and IB for the balance, each with its own date.
A price that differs from the PO: IP, with your price, so the customer can dispute it before the invoice.
Then follow the customer’s change rule. Dot Foods wants updated 855s for changes until the order ships [1]. Gentex forbids resending a changed 855; the change goes to its planner directly [2]. Either way, customers that score suppliers on OTIF (on-time in-full) count a missed confirmed date against you (OTIF guide).
4010 or 5010
Check which X12 version your customer uses: ISA12 reads 00401 for 4010 and 00501 for 5010. Every guide we read (Dot Foods, Gentex, Polaris) is 4010 [1][2][6]. The order and line codes in this guide appear in both versions [7][8]; map to the guide you were sent.
What is in an 855: the segments in plain words
Your customer’s EDI guide says which of these are required. Polaris, for example, requires only ST, BAK, REF, PO1, ACK, CTT and SE [6].
Segment | What it says |
|---|---|
ISA, GS | The envelope: who sends, who receives, when, test or production |
ST | Start of an 855 and its control number |
BAK | The customer’s PO number and date, and your answer for the whole order |
REF | Reference numbers, such as your own sales order |
DTM | Dates for the whole order, such as the scheduled ship date |
N1 | Parties: ship-to, bill-to, ship-from |
PO1 | One PO line, echoed: number, quantity, unit, price, part numbers |
ACK | Your answer for that line: status, quantity, unit and date |
CTT | Number of lines |
SE, GE, IEA | Trailers that close the 855 and the envelope |
A sample 855, decoded line by line
The customer’s PO asked for three lines. Commas replace the asterisks; the envelope is left out.
Segment as sent | What it means |
|---|---|
ST, 855, 0001 | Start of an 855, control number 0001 |
BAK, 00, AC, 4500012345, 20261102 | Original acknowledgment (00), accepted with changes (AC), for PO 4500012345 dated 2 November 2026 |
N1, ST, Northfield Plant, 92, 0042 | Ship to the customer’s location 0042 (92 means the customer assigned the code) |
PO1, 1, 100, EA, 12.40, , BP, 6204-2RS | Line 1: 100 each at $12.40, customer’s part 6204-2RS |
ACK, IA, 100, EA, 068, 20261110 | Line 1 accepted in full; ships 10 November (068 is the scheduled ship date) |
PO1, 2, 500, EA, 0.86, , BP, HX-1032 | Line 2: 500 each at $0.86 |
ACK, IQ, 300, EA, 068, 20261110 | 300 of the 500 ship 10 November |
ACK, IB, 200, EA, 068, 20261201 | The other 200 are backordered to 1 December |
PO1, 3, 40, EA, 33.50, , BP, BRG-77 | Line 3: your price is $33.50; the PO said $31.00 |
ACK, IP, 40, EA, 068, 20261110 | Line 3 accepted with a price change |
CTT, 3 | Three lines |
SE, 12, 0001 | 12 segments from ST to SE, same control number |
BAK02: the answer for the whole order
Code | When to use it |
|---|---|
AD | Every line accepted as ordered, with line detail |
AC | Accepted, some lines changed; the ACK segments say how |
AK | Accepted, with no line detail sent |
AE | Accepted; only the changed lines are listed |
RD | Rejected, with the line reasons |
RJ | Rejected outright, no detail |
RO | Rejected, with a counter offer |
Codes from the X12 element list [7]. BAK01 marks a first acknowledgment (00) or a replacement (05) [9]; some customers, Dot Foods among them, accept only 00 [1].
ACK01: the answer line by line
Code | Meaning |
|---|---|
IA | Item accepted |
IQ | Accepted, quantity changed |
IP | Accepted, price changed |
DR | Accepted, date rescheduled |
IB | Backordered |
BP | Partial shipment, balance backordered |
IS | Accepted, substitution made |
IC | Accepted, changes made |
ID | Item deleted |
IR | Item rejected |
R2 | Rejected, invalid item or part number |
ACK02 and ACK03 give the quantity and unit; ACK04 and ACK05 give a date and its kind, such as 068 for the scheduled ship date or 067 for the scheduled delivery date [8][10]. The full list holds 26 line codes; these are the common ones.
855 vs 856 vs 810, and the others
Document | What it says, and when |
|---|---|
850 Purchase order | What the customer wants; sent first |
855 PO acknowledgment | What you will ship, and when; after the 850 |
860 PO change | The customer changes the order before shipping |
865 PO change acknowledgment | You accept, reject or propose a change |
856 Ship notice (ASN) | What is on the truck, sent when it ships |
810 Invoice | What the customer owes, after it ships |
997 Functional acknowledgment | The file arrived and parsed; after any of the above |
Names from X12’s transaction set list [11].
If you are the buyer
Small suppliers often confirm by email or PDF, or not at all. Give every PO a confirmation due date and check each reply against it on part, quantity, price, date and terms: how to get suppliers to confirm ship dates has the method, and the purchase order acknowledgement reader lays an emailed reply out against the PO.
Answering each PO inside the 855 window
When an 850 lands, Morsa enters the sales order in your ERP and works out each line’s answer from stock, open production and supplier dates, so the 855 goes out inside the window.
It drafts the line answers (IA, IQ and IB with dates, IP where the price differs) for the order desk to approve.
When a promised date slips, it drafts the updated 855, or the note to the customer’s planner where the guide forbids one.
To see it on your own customer POs, book a 30-minute walkthrough.
What to do this week
Find each customer’s 855 deadline, change rule and X12 version in its EDI guide, and write them beside the customer.
Ask your EDI provider how often it checks your mailbox, and shorten it if the wait eats your window.
Set the 855 to go out on order entry, not on shipment.
Check that BAK03 echoes the PO number exactly, with no added prefix.
Test one 855 with your customer’s EDI team before go-live.
Customer not on EDI? The free order acknowledgement template builds the same line-by-line answer, with these codes, as a PDF, Word or Excel file to email.
Sources
Dot Foods, Supplier 855 Purchase Order Acknowledgment, version 004010: https://www.dotfoods.com/globalassets/corporate/pdfs/supplier-edi/855-purchase-order-acknowledgment.pdf (read 8 November 2026)
Gentex, EDI 855 Purchase Order Acknowledgement Specification (version 1.9): https://www.gentex.com/files/supplier-information/Gentex-EDI-855-Purchase-Order-Acknowledgement-Specification-Document.pdf (read 8 November 2026)
SPS Commerce, EDI 855 Purchase Order Acknowledgment: https://www.spscommerce.com/edi-document/edi-855-purchase-order-acknowledgment/ (read 8 November 2026)
TrueCommerce, EDI 855: https://www.truecommerce.com/edi-transaction-codes/edi-855 (read 8 November 2026)
Stedi, X12 4010 BAK segment (BAK03 purchase order number, BAK04 PO date): https://www.stedi.com/edi/x12-004010/segment/BAK (read 8 November 2026)
Polaris, 855 Purchase Order Acknowledgment, X12 4010 supplier specification: https://polarissuppliers.portal.covisint.com/documents/25381610/27933936/EDI_Specification_855.pdf/092351c6-8542-426f-83fd-46e464d5c0f1 (read 8 November 2026)
Stedi, element 587, Acknowledgment Type (BAK02 codes), X12 4010 and 5010: https://www.stedi.com/edi/x12-004010/element/587 and https://www.stedi.com/edi/x12-005010/element/587 (read 8 November 2026)
Stedi, element 668, Line Item Status Code (ACK01 codes, 26 in 5010), and the ACK segment: https://www.stedi.com/edi/x12-004010/element/668 , https://www.stedi.com/edi/x12-005010/element/668 and https://www.stedi.com/edi/x12-004010/segment/ACK (read 8 November 2026)
Stedi, X12 4010 element 353, Transaction Set Purpose Code: https://www.stedi.com/edi/x12-004010/element/353 (read 8 November 2026)
Stedi, X12 4010 element 374, Date/Time Qualifier: https://www.stedi.com/edi/x12-004010/element/374 (read 8 November 2026)
X12, Transaction Sets (850, 855, 856, 860, 865, 810, 997 definitions): https://x12.org/products/transaction-sets (read 8 November 2026)
