FiberPlex TD-7280 - Manual (Page 16)

E&M Configurations
Type II ‐ Two signaling nodes can be connected back‐to‐back. Type II uses four leads for supervision signaling:
E, M, SB, and SG. During inactivity the E‐lead and the M‐lead are both open. The PBX indicates an off‐hook
condition by connecting the M‐lead to the signal battery (SB) lead on the tie line equipment side. The router
indicates an off‐hook condition by connecting the E‐lead to the signal ground (SG) lead on the trunk circuit
side.
Type III ‐ This is not commonly used in modern systems. Type III uses four leads for supervision signaling: E, M,
SB, and SG. During inactivity the E‐lead is open and the M‐lead is connected to the signal ground (SG) lead on
the tie line equipment side. The PBX indicates an off‐hook condition by disconnecting the M‐lead from the
signal ground (SG) lead and connecting it to the signal battery (SB) lead on the tie line equipment side. The
router indicates an off‐hook condition by connecting the E‐lead to ground on the trunk circuit side.
Telephone Exchange FOI(TD)-7280 FOI(TD)-7280 Carrier System
Current Detect
E Lead
SG Lead
M Lead
SB Lead
Voice TX
Voice RX
-48V
13&14
1&2
23
22
24
10
11
1&2
13&14
23
22
24
10
11
Fiber
Current Detect
E Lead
SG Lead
M Lead
SB Lead
Voice TX
Voice RX
-48V
Telephone Exchange FOI(TD)-7280 FOI(TD)-7280 Carrier System
Current Detect
E Lead
SG Lead
M Lead
SB Lead
Voice TX
Voice RX
-48V
13&14
1&2
23
22
24
10
11
1&2
13&14
23
22
24
11
Fiber
Current Detect
E Lead
SG Lead
M Lead
SB Lead
Voice TX
Voice RX
-48V