Connecting FXS Interfaces

The device interfaces with the FXS analog telephone equipment (e.g., fax machines, modems, or telephones) through the 50-pin Telco connectors provided on the FXS blades. For more information on the FXS blades, see FXS Blades.

Safety Notice:

Make sure that the FXS ports are connected to the appropriate, external devices; otherwise, damage to the device may occur.
FXS ports are considered TNV-2.

FXS Outdoor Cabling and Power Surge Protection:

The device includes an integrated secondary surge protection, but does not include primary telecom protection!  When the FXS telephone lines are routed outside the building, additional protection - usually a 350V three-electrode Gas Discharge Tube (GDT) as described in ITU-T K.44 - must be provided at the entry point of the telecom wires into the building (usually on the main distribution frame / MDF), in conjunction with proper grounding. The center pin of the GDT (MDF grounding bar) must be connected to the equipotential grounding bus bar of the Telecommunication room.
Failing to install primary surge protectors and failing to comply with the grounding instructions or any other installation instructions, may cause permanent damage to the device!
The device complies with protection levels as required by EN 55035 / EN 300386. Higher levels of surges may cause damage to the device.
To protect against electrical shock and fire, use a minimum of 26-AWG wire size to connect the FXS ports.

To configure the current (mA) that the device supplies to the FXS ports in off-hook state, use the EnhancedFXSLineCurrent parameter. Configuration is applicable only to the first and last ports (e.g., 1 and 24) on each FXS connector. For more information, refer to the User's Manual.

The FXS cabling specifications include the following:

Cable: You can use any of the following cables:
AudioCodes orderable FXS Patch Panel (see Connecting FXS Interfaces using AudioCodes FXS Patch Panel)
AudioCodes orderable Centronics cable connector (10 m) to open leads, which needs to be connected to a distribution panel (see Connecting FXS Interfaces using Centronics Cable)
Third-party, main distribution frame (MDF) connector (see Connecting FXS Interfaces Directly to an MDF)
Connector Type: 50-pin Telco

50-pin Telco Connector

Connector Pinouts:

50-pin Telco Connector Pinouts

FXS Phone Channel (Ports)

Connector Pins

1

1/26

2

2/27

3

3/28

4

4/29

5

5/30

6

6/31

7

7/32

8

8/33

9

9/34

10

10/35

11

11/36

12

12/37

13

13/38

14

14/39

15

15/40

16

16/41

17

17/42

18

18/43

19

19/44

20

20/45

21

21/46

22

22/47

23

23/48

24

24/49

25 for Analog Lifeline

25/50

For analog Lifeline cabling, see Connecting the FXS Analog Lifeline.