VIRTUAL ACCESS
In ISDN mode, the CPU manages the T2 and T0 accesses of the LIOP and LIOB boards like accesses of the standard PRA and BRA ISDN boards.
The multiplexed channels common to the LIOP, LIOB and LIOX boards are seen as virtual accesses with their own signaling, B Data channel and B Voice channels.
The CPU configures a multiplexed B channel before switching it onto a B channel of a physical interface, using the message: CPU_CPL_MSG_VIRTUAL_ACCESS_SETUP.

T0/T2 Access No.
Access Type
Consult mode
This attribute gives the identification No. and the access type which were defined when the virtual access was included in a trunk group or a link (Virtual access type in TRUNK GROUPS or LINK BUS ACCESSES):
(The virtual access types possible are Voice-Switched/Voice-Leased/Transfix-Leased/Tfx-Frame Relay).

Network Mode
Network mode concerns the commissioning of level 2 (see CCITT specification). It is used for private link requirements where the protocol of the public switched network must be simulated on one of the ends of the link.
NO : user mode,
YES: network mode.
ONE END MUST BE IN NETWORK MODE (POSITION YES), THE OTHER END IN USER MODE (POSITION NO).

Min Voice Jitter Buffer
Minimum delay to be applied to voice (in ms).
0 by default.

Max Voice Jitter Buffer
Maximum delay to be applied to voice (in ms).
0 by default.

Min Fax Jitter Buffer
Minimum delay to be applied to fax (in ms).
60 by default.

Max Fax Jitter Buffer
Maximum delay to be applied to fax (in ms)
120 by default.

Mux
Multiplexing weighting factor: voice / bit rate delay balance allocated to the data.
This coefficient is used to adjust the TQUICC0 delay (transfer delay).
TQUICC0: Transmission time of Voice/Data packets on the B channel by the QUICC (Processor for allocation of internal PCMs to LIO boards).
Default: 100
Minimum value: 100, maximum delay and rate
Maximum value: 120, zero delay

Information Size
Maximum number of bytes in an information frame
Default: 260

SSCOP UU Size
Maximum size in bytes of the field SSCOP_UU (user to be used in the connection check frames).
Default: 260

CC Timer
Connection control time delay.
Default :1 sec

POLL Timer
Receiving entity polling time delay.
Default: 500ms

NO RESPONSE Timer
Maximum time accepted without response from the receiving entity.
Default: 5 sec

KEEP ALIVE Timer
Polling time delay when no data is exchanged.
Default: 2 sec

Inactivity Timer
Idle time delay, maximum time without polling between receiving entities
Default: 15 sec

Max PDU Control
Maximum number of PDU connection check frames transmitted before reception of an acknowledgement
Default:4

Max PDU Data
Maximum number of PDU data frames transmitted before polling the transmitting entity.
Default : 128

N S N R Field Size
Size of fields N(S), N(MR) and N(R) in bytes
Default:1

Bit rate
The rate identifies the type of compression.
The value 56K must be used if one of the two 4400 using this virtual access has a compression support of T1-CAS type (the real rate is then 56 K in this case). In any other cases, the value must be 64K.

Use of volume in system
YES: the Volume on boards with compressors attribute of the facilities customization object (in Installation) is used.
NO: Local Volume above is used.

Local volume (dB)
The local volume is used if Using the system volume is set to NO.
The local volume (in Decibel) allows a multiplier factor to be injected in the compression board DSP output. It is applied to each communication compressed.