L-3 Communications CEU, User Manual

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STE User’s Manual Calls
Rel. 2.6 7-1
CHAPTER 7 CALLS
Procedures for voice operations are divided into 6 major areas:
Paragraph
7-1, GENERAL MANAGEMENT
Paragraph 7-2, PSTN VOICE CALLS
Paragraph 7-3, ISDN VOICE CALLS
Paragraph 7-4, TRI-TAC VOICE CALLS
Paragraph 7-5, BDI VOICE CALLS
Paragraph 7-6, VOICE CALL FAILURES
All operations dealing with 5ESS-8510 switches are addressed in Chapter 9 .
7-1. GENERAL MANAGEMENT
Your Office and Tactical STE (Secure Terminal Equipment) supports three modes of calls: Non-secure
Voice (NSV) and Secure Voice (SV) addressed in this chapter and Secure Data (SD), which is addressed
in
Chapter 8 . Remote voice operation is only available with the CEU, STE-R, STE-RI and STE-RT as
directed in Chapter 8 .
Access to these modes depends on how the terminal’s “Initial Secure Mode” setting was established by
the TPA (Terminal Privilege Authority). There are three Initial Secure Modes: Traditional, Auto-Secure,
and Secure-Only.
•
Traditional: When you initiate a call, the STE automatically initiates a non-secure voice call
unless you manually select secure voice or secure data via the Soft Keys. When you receive a
call, the STE attempts to connect in non-secure mode unless the far end (calling) terminal has
initiated a secure call.
•
Auto-Secure: When you initiate a call, the STE automatically initiates a secure voice call unless
you manually select a non-secure voice or secure data via the Soft Keys. Incoming calls will be
connected in the secure mode.
•
Secure-Only: When you initiate a call or receive a call the STE will always connect in secure
voice or secure data. Non-secure calls cannot be made in this mode.
When the STE is connected to an ISDN service, it places “Auto-Secure” and “Secure-Only” mode calls on
a Data Bearer service, if it is available to the far end terminal (called party). The “Traditional” mode calls
are placed on a Voice Bearer service. To use STE signaling, which provides high quality secure voice
and higher data rates, a digital network path from end-to-end is required. Data Bearer service guarantees
a digital network path. Voice Bearer service does not guarantee a digital network path; however, it often
provides a digital network path, especially on local calls. If a call is initiated on a Voice Bearer (traditional
mode), the STE can execute a test with the far end terminal to determine if both the network and far end
terminal will support STE signaling. This can be accomplished by enabling STE on Voice Bearer. This
allows VBSCT (Voice Bearer Secure Capable Test) to be performed. If VBSCT passes, the STE initiates
STE security signaling; if the test fails or it is disabled, the STE utilizes STU-III or SCIP signaling. To
improve the probability of VBSCT success, the STE utilizes only a portion of the B-channel bandwidth
that supports standard STE secure voice (ADPCM). However, it limits the secure data rate to 38.4 kbps
instead of the 64 kbps available on a true Data Bearer service, and 128 kbps on bonded Data Bearers. If
VBSCT fails, or it is not enabled, the resulting STU-III signaling supports CELP voice and data to 9.6 kbps
or SCIP signaling supporting MELP or G.729D.
If your STE is configured PSTN, it will operate in the SCIP (Future Narrow Band Digital Terminal/ Secure
Communications Interoperability Protocol) and STU-III modes. If your STE is configured for TRI-TAC (Tri-
Service Tactical), BDI-530A or BDI-232 (serial Black Digital Interface) it will operate in the STU-III mode
only.
The display samples used in this Chapter are based on the STE’s Initial Secure Mode set to “Traditional”
(default setting), unless otherwise noted.