Tracksales integrates with the Kenya Revenue Authority (KRA) Tax Invoice Management System (TIMS) using the Tremol G03 Type C fiscal device. When enabled, finalized invoices and credit notes are transmitted to your KRA Control Unit in real time for tax compliance. This guide covers how TIMS works for invoices and credit notes (separate from POS Tremol TIMS).

1. Overview

The same Tremol G03 Type C device and configuration used for Point of Sale can also transmit invoices and credit notes to KRA. When you finalize an invoice or create a credit note from an invoice that has TIMS metadata, Tracksales sends the transaction to the Tremol device. The device returns Control Unit (CU) information—invoice number, serial, QR code, and timestamp—which is stored and displayed on printed and emailed documents.

Setup is shared with POS: configure Settings → Preferences → Tax → KRA Tax Transmission → TIMS with your Tremol device details. See Tremol TIMS Setup & Configuration for the full setup steps.

2. When Tremol Transmission Happens

Transmission occurs automatically for invoices and credit notes when certain actions are completed. It does not run when TIMS is disabled or when the Tremol device is unreachable.

Action What is sent to Tremol
Finalize an invoice Invoice with all line items (positive quantities)
Create a credit note from an invoice Credit note linked to the original invoice's CU invoice number
Void an invoice Credit note to reverse the original invoice
Void a credit note Credit note to reverse the original credit note

3. Invoices

When you Mark as Finalized to finalize an invoice:

  • Tracksales opens an invoice on the Tremol device
  • Adds each line item with price, quantity, tax class, and tax rate
  • Closes the receipt and receives the Control Unit invoice number, serial number, PIN, and QR code
  • Stores this metadata in the invoice record for audit and for linking future credit notes

If the customer has a tax identifier (KRA PIN), it is sent to the device for inclusion on the receipt. Draft invoices are only transmitted when you finalize them; they are not sent to Tremol while in draft status.

4. Credit Notes

Credit notes are transmitted to Tremol only when they are created from an invoice that has TIMS metadata. When you create a credit note:

  • Tracksales looks up the original invoice's Control Unit invoice number (stored in metadata)
  • Opens a credit note on Tremol linked to that original invoice
  • Adds the credited items (as positive quantities on the credit note)
  • Closes the receipt and stores the credit note metadata

⚠️ Important

Credit notes can only be transmitted when the source invoice was finalized with TIMS enabled and has metadata. Credit notes created from invoices that were finalized before TIMS was enabled, or from invoices that failed transmission, will not be sent to Tremol. Standalone credit notes (not created from an invoice) are not transmitted.

5. Voiding Invoices and Credit Notes

When you void an invoice:

  • Tracksales checks that the invoice has TIMS metadata (was transmitted)
  • Opens a credit note on Tremol to reverse the original invoice
  • Adds all original line items with the same quantities and prices
  • Closes the receipt and updates the invoice metadata

When you void a credit note that has TIMS metadata:

  • Tracksales opens a credit note on Tremol to reverse the original credit note
  • Uses the stored CU invoice number from the credit note metadata

You cannot void an invoice that has credit notes applied to it. Void or remove the credit notes first, then void the invoice. If you void an invoice or credit note that was never transmitted to Tremol (e.g. made before TIMS was enabled), no Tremol transmission occurs.

6. CU Information on Documents

When an invoice or credit note has TIMS metadata, a CU Information block appears on printed and emailed documents. This block includes:

  • Date and Time — from the Control Unit
  • Serial — Device serial number
  • CU Invoice Number — Control Unit invoice number (required for returns and voids)
  • QR code — For KRA verification

CU Information appears on invoice and credit note print templates (classic and 80mm formats). It does not appear on delivery notes (which are for transport purposes only). The layout and placement may differ slightly between the classic and 80mm formats.

7. Metadata Stored

Each invoice and credit note record stores TIMS metadata in the metadata column. For invoices:

  • tims — Contains cuDateTime, cuInvoiceNum, cuSerialNumber, cuQRcode

For credit notes created from an invoice:

  • timsReturn — Contains the credit note's CU details (cuDateTime, cuInvoiceNum, cuSerialNumber, cuQRcode)

This metadata is used for document printing, future void operations, and audit trails.

8. Troubleshooting

Common errors and solutions:

  • "Your KRA Control Unit is down or misconfigured" — Check that the Tremol device is powered on, connected to the network, and that the URL, IP, port, and password in Tax settings are correct. Ensure the device is reachable from your server.
  • "Original sale has no CU invoice number for return" — The source invoice was not transmitted to Tremol (e.g. finalized before TIMS was enabled). You cannot create a credit note for that invoice through Tremol.
  • "Failed to open Tremol invoice" / "Failed to close Tremol receipt" — The device may be busy, out of paper, or in an error state. Check the device status and try again.

💡 Related

For POS Tremol TIMS (sales, returns, exchanges, voids at the register), see POS: Tremol TIMS & KRA Integration. For creating invoices and credit notes, see Invoice Management and Credit Notes. For tax and transmission settings, see Account Settings and your organization's Tax preferences.