# FAQs

Source: https://developer.avalara.com/services-calculation-en/transactions/faqs/

# FAQs

What is CEPOM?

CEPOM is a registration mechanism created by cities to qualify and recognize the legal registration of service providers established in other cities (other jurisdictions). This is a way that cities found to make sure that service providers delivering services within their jurisdictions are compliant with the jurisdiction in which they are established. Service Providers that do not register with the local CEPOM are subject to local tax via withholding imposed as a buyer obligation. The CEPOM registration is voluntary but eliminated the double taxation for ISS (city tax on services). Not every city has a CEPOM registration process in place as not all cities require withholding from Service Providers based in other jurisdictions.

What is RPS?

The RPS is a service receipt issued as a payment receipt when services are rendered. They are later substituted by the NFS when this is issued.  This is done so that NFS can be processed in batches as some cities can't offer or maintain a real-time invoicing service.

Who is responsible for controlling the RPS number?

As previously mentioned, the RPS is a temporary and sequential number of the Service Invoice, and this number must be controlled by the invoice issuer (in this case the provider or its ERP). After analysis and approval by the municipality system, this RPS will receive an NFSe number (this one controlled exclusively by the city hall system). However it is important to understand that they are not sequentially correlated, for example:You can submit RPS number 10, and receive approval with NFSe number 3.Then send an RPS number 11, and receive approval from NFSe number 4.In sequence, send RPS number 12, and for some reason, this RPS may be pending approval.Even so, you can follow your process, and send RPS number 13 and receive approval from NFSe number 5.This way, as soon as RPS number 12 is approved, it will become NFSe number 6, if there are no other RPS's approved before.In short, for control purposes, the ERP must be the one that controls the RPS number, which was sent to the municipality system. And once the approval of this RPS is received, an NFS-e number will be returned, and this should be part of the attributes that demonstrate that this specific NFS-e number belongs to an RPS previously issued by the RRP.

Why should I inform where the service will take place?

Determining the correct calculation for service invoices is a complex process for the calculation engine, as it is necessary to combine the legislation between the places where both companies are established and where the service will be performed. That's why it's important to provide this data in the request call.

[Previous](/for-review-only/en/leila-paul/services-calculation-en/transactions/important_points_response_payload)

[Next](/for-review-only/en/leila-paul/services-calculation-en/functional_review)