In order to approach a.LEGEND system implementation with tie trunks it is really only necessary to know which signaling formats are supported and to determine which of these supported formats are required. The LEGEND system with the 400EM module supports Type 1 E&M Standard, Type 1 E&M Compatible, and Type 5 tie trunks.
The transmit and control signals for each signaling type are:
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| Type 1 | Standard | ground | battery | open*/bat | ground |
| Type 1 Compatible | open*/bat | ground | ground | open*/bat | |
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| Type 5 |
| open | ground | open | ground |
* Note: An open circuit is preferred over battery voltage.
AS its operation implies, the successful implementation of a tie trunk format will be dependent on matching the characteristics of both of the switching systems it connects. The preferred signaling formats for a tie trunk terminating in the MERLIN LEGEND system are:
TERMINATING SYSTEMS
FROM | TO | DESCRIPTION |
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LEGEND | S25/S75/Definity | |
LEGEND | S25/S75/Definity | |
LEGEND | S85 | |
LEGEND | S85 | |
LEGEND | Dimension | |
LEGEND | Dimension | |
LEGEND | OTHER | |
LEGEND | OTHER | |
LEGEND | LEGEND | Same site |
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| interbuilding |
LEGEND | MERLIN II | Same site |
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| interbuilding |
NEAR END |
| FAR END |
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MERLIN LEGEND | Protected/ | MERLIN LEGEND | Protected/ |
SIGNALING MODE Unprotected | SIGNALING MODE Unprotected | ||
Simplex Type 5 |
| Simplex Type 5 |
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Simplex Type 5 |
| Simplex Type 5 |
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Simplex Type 5 |
| Simplex Type 5 |
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Simplex Type 5 |
| Simplex Type 5 - |
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E&M Type 1 Crept | Unprot | E&M Type 1 Std | Prot |
Type 1 Crept | Prot | Type 1 Std | |
E&M Type 1 Crept | Unprot | E&M Type 1 Std | Unprot |
E&M Type 1 Crept | Prot | E&M Type 1 Std | ** |
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Simplex Type 5 |
| Simplex Type 5 |
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Simplex Type 5 |
| Simplex Type 5 |
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** Note: Plus a protection unit a little getting use to.