258
SX-200 ICP MX Technician’s Handbook
Test/Verify (DID)
• Verify the far-end circuits by the use of a standard telephone for
outgoing calls.
• Verify the near-end circuits by connecting to known working DID/Loop
circuits.
• Verify that appropriate voltages are present on Tip-Ring in each call
state.
• During off-hook condition, 20-25 mA should be drawn from the far-end.
Table 52: Direct Inward Dial/Loop Trunk Summary
Signal
DID/Loop Trunk PBX
Outgoing
DID/Loop Trunk PBX
Incoming
Seize Tip-Ring leads are activated
(shorted); Loop Current flows in
line
Tip-Ring leads are
activated (shorted); Loop
Current flows in line
Seize
Acknowledgment
Immediate Dial - Tip-Ring leads
stay active
Outgoing Wink - Tip-Ring leads
toggle
Loop Current direction Delay
Dial - Tip-Ring leads reverse
Loop Current following seizure;
reverse again when ready to go
Immediate Dial - Tip-Ring
leads stay active.
Incoming Wink - Tip-Ring
leads toggle Loop Current
direction
Digits Loop Current toggled (Rotary)
or DTMF
Loop Current toggled
(Rotary) or DTMF
Stop Dial Tip-Ring leads reverse Loop
Current direction; forward again
when ready
—
Receipt of Digits Audible Tones - Busy, Reorder,
Ringback dependent upon
digits dialed and called party
condition
Audible Tones - Busy,
Reorder, Ringback
generated and sent to
calling party dependent
upon digits received and
state of called party
Answer
Supervision
Current flow in Tip-Ring is
reversed
Current flow in Tip-Ring is
reversed
Disconnect
Supervision
Near or Far-end termination:
Loop Current broken
Near or Far-end termi-
nation: Loop Current is
broken
