I looked but didn't find many options available. I require a VoIP solution that is suitable for multiple users, specifically using asterisk. It should be able to accommodate small-scale use, even if it is open to others.

In my current situation, I have a few clients who require separate instances (and IP for each), and using standard releases like PIAF helps to keep everything uniform.

Unfortunately, most of the options I found were quite costly and designed for large carriers.

Are there any other solutions out there that I may have missed which would be a better fit?

Using an asterisk-based solution may not always be the best option, especially since other alternatives such as FS and Yate are quickly catching up in this department.

Instead of utilizing full-featured virtual machines for each client's PBX instance, many companies have started using Linux containers which provide a centralized and more efficient approach.

If you're looking for a partitioned VoIP switch service that can be distributed to each client within the base system, then consider using Kazoo at 2700 MHz. It's recommended to avoid asterisks and to use FS for multimedia and Kamailio for SIP proxy instead.

Interestingly, one of the real Kamailio developers was hired to write code for Kazoo. In addition, AG Projects also offers a SIP Thor alternative (ag-projects.com).

To install asterisk and asterisk-dahdi, use "sudo apt-get install" command. The DAHDI driver is responsible for the operation of telephony interface cards which can be installed directly into the server or operating over TDM over IP, from Digium, Openvox, etc.

However, installing interface cards in virtual machines can be quite tricky.

While searching for new articles about Asterisk, I stumbled upon a headline that caught my attention but it turned out to be just advertising services without any useful information.

The article mentions a business center providing telephony services, but it fails to provide any instructions on how to connect and use these telephony services remotely.

Despite internal numbers being of little interest, there are still dozens of messaging and calling services available for free that are commonly used.

There are several VoIP solutions available that can meet your requirements for multiple users and compatibility with Asterisk. While some options may be designed for larger carriers, there are still affordable solutions suitable for small-scale use. Here are a few alternatives you may have missed:

1. FreePBX: This is an open-source PBX platform built on Asterisk. It offers a user-friendly interface and supports multiple users and instances. FreePBX has a large community and many add-ons available.

2. Elastix: Another open-source PBX platform based on Asterisk. Elastix provides a range of features including call management, voicemail, fax, and video calling. It also supports multiple users and instances.

3. 3CX: Although it's not built on Asterisk, 3CX is a popular VoIP solution that offers a free edition for up to eight simultaneous calls. It supports multiple users and has various deployment options, including self-hosted and cloud-based.

4. Issabel: Derived from the original Elastix codebase, Issabel is an open-source PBX system with many features, including support for multiple users and instances. It provides an easy-to-use interface and has a supportive community.

Here are a few more VoIP solutions that you may find suitable for your needs:

1. FusionPBX: FusionPBX is an open-source PBX system that can work with Asterisk. It provides a rich set of features, including multi-tenant support, which allows for separate instances for different clients. FusionPBX offers flexibility and customization options.

2. Kamailio: Kamailio is an open-source SIP server that can be used as a high-performance solution for handling large volumes of VoIP traffic. It can work alongside Asterisk or other PBX systems, providing scalability and reliability.

3. VitalPBX: VitalPBX is an open-source PBX platform that supports multi-tenant deployment. It offers features such as call routing, recording, voicemail, and more. It's designed to be cost-effective and user-friendly.

4. 2600Hz Kazoo: Kazoo is an open-source telephony platform that supports multi-tenant deployment and integrates with Asterisk. It provides a range of features including call routing, conferencing, voicemail, and messaging. Kazoo also has a robust API for customization.