Carrier Access AB II The interpretation of the signaling bits for ESF framing are as follows:

Analog Ports
8-7
The interpretation of the signaling bits for ESF framing are as follows:
The following abbreviations are used in this table:
LCF - Loop current feed
RLCF - Reverse loop current feed
LCFO - Loop current feed open
LO - Loop Open
LC - Loop closure
RG - Ring ground
ESF Framing Format
See the legend at the end of this table for explanations of abbreviations.
Signaling Type State Receive (Network-to-
CI) Transmit ( CI-to- Network)
Rx Tx ABCDABCD
Loop-start signaling
(FXO-FXS) LCF LO (on hook)01010101
Ringing LC (off hook)00001111
Loop-start signaling
with RLCF (FXO-
FXS)
LCF LO (on hook)01010101
RLCF LC (off hook)01001111
LCFO 1111
Ringing 0000
Ground-start
signaling (FXO-
FXS)
LCF LO (on hook)01010101
LCFO LC (off hook)11111111
Ringing RG (service
request) 00000000
Ground-start
signaling with
RLCF (FXO-FXS)
LCF LO (on hook)01010101
RLCF LC (off hook)01001111
LCFO RG (service
request) 11110000
Ringing 0000
Loop-reverse-
battery signaling
(DID) (DPO-DPT)
LO LCF 00000000
LC RLCF 11111111
Network-provided
reverse battery
(enhanced 911
apps) (DPT-DPO)
LCF (on
hook) LO (on hook)00000000
RLCF (off
hook) LC (off hook)11111111
E&M signaling on hook on hook 00000000
off hook off hook 11111111
D4 (SF) Framing Format