Instruction manual
Tie Trunks
2-42
Installation, SPM, Maintenance, and Troubleshooting Supplement
DIP switches 1, 2, 6, and 7 determine whether the tie trunks are 
protected or unprotected. DIP switches 3, 4, 5, 8, 9, and 10 determine 
the mode. Simplex mode is always protected. Therefore the 
Protected/Unprotected settings for DIP switches 1, 2, 6, and 7 have no 
effect.
The successful implementation of a tie trunk format is dependent upon 
matching the characteristics of both PBX systems it connects. The 
preferred signaling formats for a tie trunk originating in the system are 
shown in Table 2-7.
Table 2-7.  Signaling Formats for the 400 E&M Module
Installation 
Situation
Preferred Signaling Format
From Local System System Distant Location
To 
Distant 
Location
Signaling 
Mode/Type
Protected or 
Unprotected
Signaling 
Mode/Type
Protected or 
Unprotected
MERLIN II  Same 
site co-
located
Type 5 
Simplex
N/A  Type 5 
Simplex
N/A 
System 
25/75/85 
or 
DEFINITY
Same 
site co-
located
Type 5 
Simplex
N/A  Type 5 
Simplex
N/A 
System 
25/75/85 
or 
DEFINITY
Inter- 
office
Type 5 
Simplex
N/A  Type 5 
Simplex
N/A 
Dimensio
n PBX
Same 
site co-
located
E&M Type 1C 
(Compatible)
Unprotected  E&M Type 
1S 
(Standard)
Unprotected 










