R2511-HP MSR Router Series Voice Configuration Guide(V5)

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Signaling modes
E1/T1 interfaces support these types of signaling:
• DSS1/QSIG user signaling—Adopted on the D channel between ISDN user and network interface
(UNI). It comprises a data link layer protocol and a Layer 3 protocol used for basic call control.
• ITU-T R2 signaling—Includes digital line signaling and interregister signaling. Digital line signaling
is transmitted in TS16 (ABCD bits) of E1 trunk. It conveys status information about E1 trunks to
describe whether the trunks are occupied, released, or blocked. Interregister signaling conveys
information about address, language and discriminating digits for internal calls, echo suppressor,
caller properties and callee properties in multi-frequency compelled approach (forward and
backward) in each timeslot.
• Digital E&M signaling—Similar to R2 signaling. It transmits E (recEive) and M (transMit) call control
signals similar to analog E&M signaling in TS16, alignment signals in TS0, and voice signals in
other timeslots. In digital E&M signaling, when an E1 trunk detects and sends connection signaling,
it looks at the signal in TS16. Digital E&M signaling provides three start modes, immediate, wink,
and delay, to adapt to different devices for more reliable connection.
• Digital LGS—Digital loop start signaling is used between telephones and switches to identify the
off-hook/on-hook state, while ground-start signaling is used between switches. They differ in that
the two parties in conversation must check grounding state before closing the line in the ground-start
approach.
Fax function
The FAX function is available on E1/T1 voice interfaces to set up fax channels and transmit/receive fax
data.
Protocols and standards
E1/T1 voice supports SIP and recommendations in the ITU-T H.323 framework, and G.711, G. 729, a n d
G.723.1 Annex A (5.3K and 6.3K) in ITU standards.
Table 4 Protocols supported by E1/T1
Item E1 Voice T1 Voice
Framing format
Cyclic redundancy check 4 (CRC4),
non-CRC4
Super frame (SF), extended super frame
(ESF)
Line coding format
High-density bipolar 3 (HDB3), alternate
mark inversion (AMI)
Bipolar 8-zero substitution (B8ZS), AMI
E1 and T1 configuration task list
Configuration considerations:
1. Install a VE1 or VT1 voice interface card on the router.
2. Configure basic parameters for voice interfaces.
3. Configure the corresponding voice subscriber line for each TS set.
4. Configure signaling.
Task Remarks
Configuring basic parameters for an E1 voice interface Optional.