23(57)
Datum/Date
Rev
Dokumentnr/Documentnr
Uppgjord/Prepared
Dokansv/Godkänd - Doc respons/Approved
Kontr/Checked
Tillhör/Referens-File/Reference
1999-07-15
V
1531-BDV 113 08 Uen
INSTALLATION INSTRUCTION
Faktaansvarig - Subject responsible
5.10.2
Four wire speech connection
The four wire speech and signalling connection has the benefit of not needing additional signalling wires. There are
two different types of signalling supported:
Cailho E&M-signalling (balanced battery). The two way signalling utilises common mode DC pulses via the centre
tap of the transformer. On one side a detector is connected between the -48 VDC and the centre tap of the
transformer. The other end uses opto relay M4 to switch the line to 0V (Ground). The detector reads the current flow
to ground every time M4 closes.
CEPT L1/SSAC 15 with 2280 Hz tones. In this case no DC signalling is used but instead signalling is performed by
switching on and off a 2280 Hz tone, which is detected by a tone receiver on the other side. This is only available on
index 2 boards.
Applies for switches 109, 209, 309 and 409.
Figure showing Cailho E&M signalling and CEPT L1 or SSAC 15 with tone signalling
1
2
3
on
S6 S7 S8
This switch setting inhibits signalling on E1 and M1. Only AC or DC
signalling on the four wire speech connection is used.
Switch settings
0V
DSLA
C
4A18
4A20
4C18
4C20
PBX
R
-48V
Detector
M4
LA
LB
LC
LD
autom. 2/4wire
2280 Hz
detector
2280 Hz
0V
-48V
Detector
0V
PBX or channel equipment
0V
1uF 560
Ω