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Cambodia’s mobile-first telecommunications landscape means that a significant share of business calls land on GSM networks rather than fixed lines. KHCOLO’s GSM/VoIP gateway solutions let you route those calls intelligently through your 3CX phone system, slashing mobile termination costs, enabling bulk SMS campaigns, and giving your team a single unified communications hub that spans both VoIP and cellular networks.

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UC2000-VF 16-Channel GSM/3G/4G Gateway

The UC2000-VF is a rack-mountable, carrier-grade gateway that bridges up to 16 simultaneous GSM, 3G, or 4G channels into your SIP-based 3CX environment. Designed for businesses with moderate-to-high outbound call volumes or SMS requirements, it eliminates the need to purchase separate SIM-based devices for each mobile operator you work with.

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Hardware Specifications at a Glance

VoLTE and Hot-Swappable SIM Modules: The UC2000-VF supports VoLTE (Voice over LTE), delivering HD voice quality over 4G networks — important as Cambodian carriers continue phasing out 2G infrastructure. Each of the 16 SIM slots is hot-swappable, meaning you can insert, remove, or swap SIM cards without rebooting the device or interrupting active channels. This makes operator changes and SIM rotation for anti-blocking policies completely seamless in production environments.

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Use Cases

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1. Bridging Mobile GSM Networks to 3CX

Connect the UC2000-VF to your 3CX phone system as a SIP trunk. Inbound calls from any Cambodian mobile number ring directly to 3CX extensions, queues, or IVR menus — just like calls from a fixed SIP provider. Outbound calls to mobile numbers are routed through the gateway’s local SIM cards, using domestic mobile rates instead of expensive international VoIP termination fees.
1

Insert SIM Cards

Load SIM cards from your preferred Cambodian operators (Cellcard, Smart, Metfone, or others) into the hot-swappable slots. Mix operators across slots for redundancy and least-cost routing.
2

Register as a 3CX SIP Trunk

Configure the UC2000-VF’s IP address, SIP credentials, and codec settings in the 3CX Management Console under SIP Trunks. The gateway registers like any standard SIP provider.
3

Configure Outbound Routing Rules

In 3CX, create outbound rules that send calls prefixed with Cambodian mobile codes (e.g., 01x, 07x, 08x, 09x, 096–099) through the gateway trunk for least-cost routing.
4

Test and Monitor

Place test calls across each channel. Use the UC2000-VF’s web management interface and 3CX call logs to verify connectivity, audio quality, and channel availability.

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2. Local Mobile Call Termination

For businesses that need to present a local Cambodian mobile CLI (Caller Line Identification) when dialling customers, the UC2000-VF ensures your outbound calls appear as familiar local numbers rather than international VoIP DIDs. This dramatically improves answer rates — particularly important for sales and customer service teams.
Local SIM-based termination can reduce outbound call costs to Cambodian mobile numbers by up to 60–80% compared to international VoIP routes, depending on your current provider’s mobile termination rates.

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3. Bulk SMS Sending via Automated API

The UC2000-VF exposes an HTTP/HTTPS REST SMS API that your applications can call directly to send outbound SMS messages through any of the installed SIM channels. Common use cases include:
  • Appointment reminders — automatically triggered from your CRM or scheduling system
  • OTP / two-factor authentication — send one-time passcodes to customers via local SMS
  • Marketing campaigns — bulk promotions distributed through multiple SIM channels simultaneously
  • Transactional alerts — order confirmations, payment receipts, and delivery notifications

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Full Feature List

16 Simultaneous Channels

Handle up to 16 concurrent voice calls or SMS streams — scale to multiple units for higher capacity.

Multi-Network SIM Support

Insert SIM cards from any Cambodian mobile operator. Mix networks across slots for redundancy.

VoLTE HD Voice

Crystal-clear HD audio over 4G LTE networks, future-proofing your setup as 2G is phased out.

Hot-Swappable SIMs

Replace or rotate SIM cards live without rebooting or dropping active calls on other channels.

REST SMS API

Integrate SMS sending directly into your web apps, CRM, or ERP via a simple HTTP/HTTPS API.

3CX SIP Trunk Integration

Registers natively as a SIP/2.0 trunk in 3CX — no special drivers or middleware required.

Web Management Console

Monitor channel status, SIM signal strength, call statistics, and SMS logs through a browser-based dashboard.

Least-Cost Routing

Work with 3CX’s outbound routing rules to automatically select the lowest-cost SIM for each call destination.

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Integration with 3CX

The UC2000-VF pairs directly with KHCOLO’s 3CX phone system deployments. Once registered as a SIP trunk, it participates fully in 3CX features:
  • Ring groups and call queues — inbound mobile calls join the same queues as VoIP calls
  • IVR menus — callers dialling your mobile number hear the same auto-attendant as any other caller
  • Call recording — mobile calls are recorded alongside VoIP calls in the 3CX recording library
  • Reporting — mobile call data appears in 3CX real-time dashboards and call log reports
  • Failover — if the gateway is unreachable, 3CX can automatically fall back to an alternative SIP trunk
For maximum resilience, KHCOLO recommends loading SIM cards from at least two different Cambodian mobile operators across your 16 channels. If one operator experiences a network outage, 3CX’s outbound routing rules will automatically prefer channels on the working operator.

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Getting a Gateway Deployed

Contact the KHCOLO team to discuss your call volume, SMS requirements, and preferred mobile operators. We handle procurement, rack installation, SIM configuration, and full 3CX trunk integration — so your gateway is live and routing calls from day one.