AltiGen comm ACM 5.1 - Manual (Page 431)

Appendix A: E1-R2 and E1 ISDN PRI Installations
AltiWare ACM 5.1 Administration Manual 417
4. Select Regular ISDN PRI as the Span Type, and select the Switch Mode according
to your country in the ISDN PRI Setting field, and click OK.
Figure 5. Data Link layer
What you should select in the B Channel Maintenance Message drop-down list
depends on what country you reside in (see Table 2 on page 418).