TM 11-5805-715-34/EE119-DB-MMI-010/E154 CV3478/TO 31W2-2TTC39-12
d. Outgoing Release from Circuit Switch.
b. Incoming Release from Foreign NIU.
(1) The circuit switch CPU sends ON-HOOK
(1) The foreign NIU sends RELEASE on
command to the SF adapter serving the se-
SYX to the local NIU.
lected NIU trunk.
(2) The local NIU sends RELEASE (500-
(2) The SF adapter sends RELEASE (500
msec burst of high-level tone, then
msec burst of high-level tone, then continuous
continuous low-level 2600 Hz) on the
low-level 2600 Hz) to the NIU receive pair.
transmit pair to the associated SF
(3) The local NIU sends RELEASE on SXY to
adapter in the circuit switch.
the foreign NIU.
(3) The dc scanner in the circuit switch
(4) The foreign NIU returns RELEASE AC-
detects RELEASE and notifies the CPU.
KNOWLEDGE on SYX to the local NIU.
(4) The CPU waits approximately 530
(5) The local NIU sends RELEASE
msec and then returns ON-HOOK
ACKNOWLEDGE (500 msec burst of high-
(RELEASE ACKNOWLEDGE) to the SF
level tone, then continuous low-level 2600 Hz)
adapter unless SEIZE is received from
to the associated circuit switch SF adapter.
the dc scanner during the timeout.
(6) The circuit switch dc scanner detects RE-
(5) The SF adapter sends RELEASE AC
LEASE ACKNOWLEDGE (reported by the SF
KNOWLEDGE (500 msec burst of high-
adapter as a RELEASE) and notifies the CPU.
level tone, then continuous low-level
2600 Hz) to the NIU receive pair.
2-12. Power Supply Input Protection
(6) The local NIU returns RELEASE AC-
KNOWLEDGE on SXY to the foreign
The power input protection is provided by a circuit
NIU.
breaker which trips whenever the input current
c. Outgoing Seizure .from Circuit Switch.
exceeds 150 percent of nominal value. Output
protection, except for -28 vdc circuitry, is provided
(1) The circuit switch CPU sends OFF-
by crowbar circuitry which actuates whenever an
HOOK command to the SF adapter
out- put exceeds 125 percent of nominal load
serving the selected NIU trunk.
internal rated value. The crowbar resets upon
(2) The circuit switch SF adapter sends
removal of in- put power.
SEIZE (absence of low-level 2600 Hz) to
the NIU receive pair.
(3) The local NIU sends SEIZE on SXY
to the foreign NIU.
(4) The foreign NIU returns SEIZE AC-
KNOWLEDGE on SYX to the local NIU.
(5) The local NIU sends SEIZE
ACKNOWLEDGE (absence of low-level
2600 Hz) to the associated SF adapter in
the circuit switch.
(6) The circuit switch dc scanner serving
the SF adapter detects SEIZE
ACKNOWLEDGE (reported by the SF
adapter as a SEIZE) and notifies the
CPU.
2-7
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