Auerswald COMtrexx Flex — Scalable 19" IP Telephone System up to 250 Users
Up to 250 users10 user licences incl.48 parallel calls19" rack
The Auerswald COMtrexx Flex is a rack-mounted IP telephone system for growing businesses, scalable to 250 users through floating user licences — ten are included. Each user can have up to five devices, with up to 500 registered terminals, 48 parallel calls and up to 96 freely assignable VoIP channels (trunk or user).
It mounts in a 19-inch rack with metal angles and offers 3+1 module slots: up to three 4FXS modules give 12 analogue extensions for faxes, door intercoms or lift phones, and a GbE-NET module adds a second Gigabit network port.
Before you order: System activation is required before use. Users beyond the ten included need additional floating licences, and UCC features need a paid licence plus a UCC server. Product photos show the system with optional modules fitted; the base unit ships without modules.
What's in the Box
- COMtrexx Flex base unit
- Voucher for 10 floating user licences
- Operating manual
What It Means in Practice
- Start with ten users and add licences as the team grows — no hardware change up to 250 users.
- Keep analogue devices on 4FXS modules while moving everything else to VoIP.
- Per-user voicemail and fax boxes (up to 250 each, 32 channels combined), 64 call groups and 10 conference rooms.
What Will Not Work
- No analogue extensions built in for terminals — 4FXS modules (90133) are needed for analogue phones.
- Not usable without system activation and user licences.
- Not compatible with COMpact 3000/4000 modules (2a/b, S0, 2BRI on 4000).
- No built-in DECT — use an IP DECT system for cordless phones.
Key Features
Scalable licensing
10 floating users included, up to 250 with licences.
VoIP capacity
Up to 96 VoIP channels, 48 parallel calls, G.711/G.722, T.30/T.38 fax.
Modular
3+1 slots: 4FXS for 12 analogue ports, GbE-NET for a second LAN.
Rack ready
19" mounting with metal angles, 5–65 W.
Technical Specifications
| Identification |
| Part Number |
90024 |
| EAN / GTIN |
4019377900246 |
| Brand |
Auerswald |
| Capacity |
| Users |
Up to 250 (licensable), 10 floating licences included |
| Devices |
Up to 5 per user, 500 registered terminals |
| Parallel calls |
Up to 48 |
| VoIP channels |
Up to 96, trunk or user |
| Codecs / fax |
G.711, G.722 / T.30, T.38 |
| Voicemail / fax boxes |
250 / 250, up to 32 channels combined |
| Groups / conferences |
64 call groups (40 members each) / 10 rooms |
| Address book |
2,000 contacts |
| Interfaces |
| LAN |
1x Gigabit Ethernet (2nd via GbE-NET module 90025) |
| Module slots |
3+1 |
| Analogue extensions |
Up to 12 via 4FXS modules (90133) |
| Physical |
| Power |
230 V, 5–65 W |
| Dimensions |
325 x 88 x 240 mm |
| Weight |
approx. 1.7 kg without modules |
| Mounting |
19" rack with metal angles |
| Warranty |
| Warranty |
1-Year Warranty (Singular) |
| Manufacturer Term |
Standard 24-month Auerswald manufacturer warranty (extendable under Auerswald programmes) — claims handled through Singular |
Frequently Asked Questions
How many users are included?
Ten floating user licences; more are added by licence up to 250.
Can I connect analogue phones?
Yes, with 4FXS modules — up to 12 analogue ports.
Is the firmware current?
Yes, the platform is current; firmware 2.6.4 was released in July 2026.
Singular Expert Insight · Buyer's Guide
The COMtrexx Flex suits offices from about 10 to 250 users that want one rack-mounted platform for VoIP, analogue devices and growth. Budget for licences and modules up front, and plan PoE for the IP phones with our
PoE switches.
✓ Buy it if you need a scalable, rack-mounted VoIP PBX for a growing business.
✕ Skip it if you have fewer than about 10 users and want a wall-mount box — a COMpact 4000 is simpler.
→ Also consider the COMpact 4FXS module for analogue extensions.
Not sure which licences and modules you need? Send us your user count, phones and lines and we will spec it before you order.