*This material is for reference purposes only. Information is collected from open sources and based on the technical experience of system users. Tariffs and connection terms must be clarified directly with telecom operators. Oki-Toki is not a representative or agent of the listed companies.
In Oki-Toki, the logic is configured: queues, scripts, dialer algorithms, and reporting. However, the calls themselves physically go through operator networks. Without a SIP number, the system is cut off from the outside world—it cannot receive incoming calls or make outgoing ones.
A SIP number is not a separate tool, but part of the infrastructure. If a business operates in Ukraine, using a number with the +380 code is the standard. It is perceived by subscribers as a local call, which directly affects the Answer Rate (percentage of answered calls). At the same time, the team’s geography doesn’t matter: agents can be located anywhere in the world, as long as stable data transmission is ensured.
Why provider choice affects results
At the start, people often only look at the price per minute. This is a mistake, the consequences of which become apparent when load increases. While traffic is low, the provider’s work goes unnoticed. Problems begin when delays, dropouts, or “metallic” sound occur.
Connectivity can start “falling apart” when launching mass dialer campaigns or increasing the number of simultaneous lines. At such moments, it becomes clear that the problem is not in the software or the agents. The provider is the transport layer. It determines whether a call will go through, how it will sound, and whether the client will see your number correctly.
SIP telephony providers in Ukraine
SIP-GSM (SIP Hub Україна)
Ukrainian provider specializing in converting mobile numbers of Ukrainian operators to SIP and replacing GSM gateways.
Technical data: connection of mobile numbers Kyivstar (067, 068, 096, 097, 098), Vodafone (050, 066, 095, 099), Lifecell (063, 073, 093), Ukrainian landline numbers, as well as 0-800, “hidden” (without identifiable caller ID), and international numbers—via SIP, without GSM gateways. It’s possible to convert an already active corporate SIM card Kyivstar/Vodafone to SIP format without changing the operator and without changing the number. Unlimited multi-channel SIP trunks.
Intertelecom
Ukrainian operator, previously CDMA, now operating as a mobile virtual network operator on a partner GSM/4G network.
Technical data: Mobile numbers in code 094 (SIM, eSIM, or virtual number via IT Phone app). Direct landline numbers in nine regions: Zakarpattia, Ivano-Frankivsk, Volyn, Lviv, Rivne, Chernivtsi, Ternopil, Donetsk, Luhansk. “SIP Multi-channel” service—up to 100 simultaneous connections per number. 0-800 available, number portability (MNP).
Note: after closing CDMA, the operator’s product focus has shifted to the retail segment. Corporate SIP trunk connection terms should be clarified with the operator directly.
Datagroup
National provider with a wide range of telephone products for business.
Technical data: landline numbers in cities of presence, numbers in code 0-891 (special code for IP telephony), 0-800, 0-900. Products—SIP telephony, SIP-Trunk. Multi-channel—basic feature. Network—more than 45 cities in Ukraine, including Kyiv, Lviv, Odesa, Kharkiv, Dnipro, Zaporizhzhia, Mykolaiv, Kherson, Vinnytsia, Poltava, Chernihiv, and others.
Kyivstar Business
Mobile operator with a fixed/IP telephony product line for B2B.
Technical data: Kyivstar mobile numbers (067, 068, 096, 097, 098), landline, 0-800, 0-897. “SIP PRO” tariff (launched May 16, 2025)—without physical SIM. Also packages SIP Simple 50, SIP 55, SIP 170, multi-channel SIP 800 and SIP 1700. Number portability (MNP) supported.
Lifecell Business
B2B division of mobile operator lifecell, specializing in corporate SIP/FMC telephony.
Technical data: mobile numbers in codes 063, 073, 093; direct landline numbers—Kyiv, Dnipro, Odesa, Kharkiv, Zaporizhzhia. Voice traffic encryption. Multi-channel, short internal numbering, call recording, web interface my.lifecell.ua. Number portability (MNP) supported.
Ukrtelecom
National fixed-line operator with separate B2B products SIP Trunk, SIP Line, and traditional telephony.
Technical data: two key products for business—SIP Trunk (for companies with their own IP-PBX, unlimited number of lines) and SIP Line (subscriber line + call forwarding, conference calling, voicemail). Landline and national numbers, 0-800. Per-second billing.
Chereda
Regional operator working in Kyiv, Kyiv region, and Sumy. Main business—wired internet and TV; telephony as an additional service.
Technical data: analog, digital, and IP phone lines. For clients needing 10+ lines, a solution with digital streams is offered. SIP telephony is positioned for companies with large volumes of long-distance and international calls; channels can be added without replacing equipment.
Phonet
Ukrainian telecom operator (LLC “PHONET”), providing SIP numbers and IP telephony services for business.
Technical data: landline numbers in most major cities—Kyiv, Kharkiv, Odesa, Dnipro, Lviv, Zaporizhzhia, Vinnytsia, Chernihiv, and others; mobile numbers through partnership with Ukrainian operators; 0-800; international numbers in 180+ countries. Multi-channel numbers. Porting an existing number to SIP is supported; exception—Ukrtelecom numbers, for which only call forwarding is possible.
International providers
Lexicall (Lexico Telecom)
International wholesale VoIP provider of voice termination, SMS, and DID, focused on call centers and business traffic.
Technical data: SIP trunk with A–Z termination in several quality classes. Direct inward dialing numbers (DID) in 150+ countries, including Ukraine. Details on Ukrainian cities and tariffs—only in personal account.
Zadarma
International VoIP provider with number capacity in 110+ countries.
Technical data: SIP trunk with IP or login/password authentication. Ukrainian numbers: mobile +380 91 (with SMS reception), landline Kyiv +380 44, national VoIP +380 89, national +380 63/93—number is issued after identity and address verification. Number portability (MNP) in 40 countries.
What to clarify in advance (Technical checklist)
To avoid redoing settings during operation, it’s worth asking the provider several questions before paying the invoice. These parameters directly affect system stability under load.
- Number format In what format does the provider deliver the client number? For Oki-Toki, the standard is international E.164 format (e.g., +380…). If the provider uses other prefixes, additional configuration of number transformation rules will be required.
- Authentication type Is registration by login/password or authentication by static IP (SIP trunk) used? For a stable call center, trunks are always preferable, as they eliminate problems with periodic account re-registration.
- Allowed load (CPS) The Calls Per Second parameter—how many call attempts per second does the provider allow. If you launch a dialer for 50 agents, but the provider’s limit is 2 CPS, the system will work incorrectly, and calls will be rejected on the operator’s side.
- Codec support Is the G.711 codec (alaw/ulaw) used? This is the standard for transmitting sound without quality loss. If the provider only offers G.729 (compressed format), the sound may be “compressed,” which reduces dialogue quality.
- Caller ID transmission Will your number be displayed correctly to the subscriber? It’s important to clarify in which SIP header the Caller ID is transmitted (From, P-Asserted-Identity, or Remote-Party-ID). This determines whether your number will be identified as “Anonymous” or “Spam.”
- Testing before payment Does the provider provide a test balance or free minutes for quality testing? This is necessary to measure delays (Latency) and jitter under real conditions.
How to connect a number to Oki-Toki
The integration process for any of the listed operators into Oki-Toki is standardized. After receiving data from the provider (server, login, password, or IP), you enter them into the system, configure routing rules, and can start working.
The system can use multiple providers simultaneously. A rational strategy is traffic separation:
- Inbound: received on one operator whose number has long been known to clients.
- Outbound: made through another with more favorable per-second billing terms for dialing.
- Backup: it’s always worth having a backup channel from another provider. In case of an emergency on the main operator’s side, switching routes in Oki-Toki takes a minute, which prevents team downtime.
Don’t connect all lines at once. It’s recommended to start with one number, check voice clarity, absence of echo, and correct audio file recording. Only after successful load testing does it make sense to scale the project.
A SIP number is not just a formality, but the foundation of all telephony. If everything is configured correctly at this stage, the system then works predictably. If not—technical problems will start appearing at the most inopportune moment.
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