# OpenScape Business STLSX4R — 4-Port ISDN S0 (BRI) Trunk Card

URL: https://www.promark.tr/en/products/stlsx4r
Category: Expansion Cards & Modules
Family: [OpenScape Business X3R/X5R Cards](https://www.promark.tr/en/products/osbiz-x5r-cards)

4 × S0 (ISDN BRI) trunk card for X3R/X5R. Front-panel R-series card for terminating ISDN basic rate lines.

## Key features

- 4 × S0 (ISDN BRI) ports.
- Platform: X3R / X5R — front-panel connection.
- X5R S0 ceiling: 48.
- Promark: ISDN line planning and commissioning.

## Specifications

- **Type:** ISDN BRI trunk card
- **Port:** 4 × S0 (2B+D)
- **Platform:** OpenScape Business X3R / X5R (front panel)
- **System ceiling:** 48 × S0 (X5R)
- **Mitel PN:** 50009281
- **Unify L No:** L30251-U600-A83

## Use cases

- Terminating existing ISDN BRI subscriptions at the PBX.
- Phased ISDN-to-SIP migration periods.

## For a quote and BOM

https://www.promark.tr/en/contact · +90 312 544 09 15 · destek@promark.tr