What OSCU and VSCU actually are
Both OSCU and VSCU are software control units, the part of eTIMS that signs your invoices and generates the control number and QR code. They replaced the physical control box that TIMS required. The difference is where and how the signing happens.
An OSCU, the Online Sales Control Unit, signs invoices through a live connection to KRA. A VSCU, the Virtual Sales Control Unit, can sign invoices locally and sync the data to KRA afterwards. In short, OSCU is online-first and VSCU is built to keep working offline.
For a country where power cuts and patchy connectivity are facts of life, the offline capability of a VSCU-style setup is not a nicety; it is what keeps a shop trading during an outage. The right choice depends on your volume and how reliable your connection is.
How eTIMS onboarding works with OSCU or VSCU
- 1
Start onboarding with your KRA PIN
Begin the eTIMS onboarding tied to your KRA profile and verify your identity with the code sent to your registered contact.
- 2
Choose your integration type
Select whether you will use an online (OSCU) connection or an offline-capable (VSCU) setup, usually through the POS or system you intend to run.
- 3
Connect your software
Link your POS or system so it can sign invoices. A reputable POS handles the technical side so you do not configure control units by hand.
- 4
Confirm your business and branch details
Make sure the details that will appear on invoices match iTax across every branch and device.
- 5
Issue a test invoice
Sign a test invoice and confirm the control number and QR code are produced and the data reaches KRA, online or on sync.
- 6
Roll out across tills
Once verified, extend the same setup to every till and device, so all your sales are signed consistently.
OSCU vs VSCU mistakes
Choosing online-only on a shaky connection
If your internet drops often, an online-only setup means you cannot issue invoices during outages. An offline-capable approach keeps you selling.
Trying to configure control units manually
The control unit type is plumbing. A good POS abstracts it away. Hand-configuring it is a recipe for errors and downtime.
Forgetting to test the sync
With offline signing, the real test is whether queued invoices actually reach KRA on reconnect. Confirm the sync, not just the signing.
Picking the right unit for a busy duka
A busy duka in an area with frequent power cuts onboards for eTIMS. If it relied on an online-only OSCU setup, every outage would stop invoicing and force the owner to either turn away customers or sell without compliant invoices. Neither is acceptable.
Instead the duka runs a POS with offline-capable signing. During an outage, sales continue, invoices are signed locally with control numbers, and the moment the connection returns everything syncs to KRA automatically. The customer never notices, and compliance is never broken. That offline resilience is the whole point of choosing the right control unit approach.
Trading without eTIMS-compliant tax invoices risks KRA penalties, blocked VAT input claims for your customers, and receipts a business buyer cannot expense.
Veira signs every sale to KRA eTIMS automatically, so each receipt is compliant the moment it prints, with no separate device to reconcile.
How Veira handles the control unit for you
With Veira you do not think about OSCU versus VSCU. The till is built to sign invoices and keep working offline, queuing transactions during an outage and syncing to KRA on reconnect, so you get the resilience of offline signing without configuring anything.
Onboarding connects your KRA profile correctly the first time and proves it with a test invoice. After that, every till on your account signs invoices the same way, online or offline.
Frequently asked questions
What is the difference between OSCU and VSCU?
Which control unit do I need?
Do I configure OSCU or VSCU myself?
Can I issue invoices offline with eTIMS?
Is OSCU or VSCU better for a small shop?
Does the customer see any difference?
OSCU versus VSCU sounds technical, but it boils down to one practical question: can you keep selling when the line drops? For most Kenyan businesses the answer needs to be yes, which makes offline-capable signing the smart default. Let a POS manage the control unit so you never touch it. Book a free demo and onboard with offline resilience built in.