DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Architecture
1-35Protocols
1
■Although data entering the system through an EIA port has not been
processed through a data module, the port i tself has a built-in data
module. Inside the system, p ort data is identic al to digital line data. Data
entering the system at a DCP line port c an exit at an EIA port. Conversely,
data entering the system at an EIA port c an exit at any DCP line port. The
destination data module mu st be set for Mode-2 DMI com munication.
■Voice-grade data can b e carried over a DS1 facility as l ong as the
destination equipment is a modem compatib le with the originating modem
■If a mismatch exists between the typ es of signals used b y the endpoints in
a connection (for example, th e equipment at one end is an analog
modem, and the equip ment at the other end is a dig ital data module), a
modem-pool member must b e inserted in the circ uit. When the endpoints
are on different switches, it is recommend ed that the modem-p ool
member be put on the orig ination or destination system. A mod em-pool
member is always inserted auto matically for calls to off-premise s sites via
analog or voice-grad e trunking. For internal calls, however, the systems
are capable of automatic ally inserting a mod em-pool member.
■Data cannot be carried over analog facilities unless insid e the system it is
represented as a Pulse Code Modulation (PCM)-encoded analog si gnal.
To do this for data originating at a digi tal terminal, the signal enters the
system at a digital por t and exits the system at a dig ital port. The signal
then reenters the system through a modem-p ool connection (data-mod ule
to modem to analog-port) and exits the system again at an analog port.
■Although DS1 is commonly called a trunk speed, here it names the
protocol used at layer 1 for d igital trunks. Some trunks use different
signaling methods b ut use DS1 protocol at layer 1 (for examp le, PRI and
24th-channel signaling trun ks).
Disconnect Supervision
Disconnect supervision mea ns the CO has the ability to release a trunk when the
party at the CO discon nects, and the system is ab le to recognize the release
signal. In general, a CO in the United States provid es disconnec t supervision for
incoming calls b ut not for outgoing c alls. Many other countries do not p rovide
disconnect sup ervision on either incoming or outg oing calls.
The system must provide the assurance that at l east one party on the call c an
control the dropping of the call. This avoids locking up circuits on a c all where no
party is able to send a disconnect sig nal to the system. Internal operations must
check to be sure one p arty can provide d isconnect sup ervision. An incoming
trunk that does not provide d isconnect sup ervision is not allowed to terminate to
an outgoing trunk that does not provide disco nnect supervision.
In a DCS environment, an incoming trunk without disc onnect supervision c an
terminate to an outgoing DCS trunk c onnecting two nodes. The inc oming trunk is
restricted from being tran sferred to a party without disc onnect supervision on the
terminating node.