PBXserver, Version 2.1					SPD 29.23.02

DESCRIPTION

The PBXserver is an Ethernet based terminal server.  It links to Digital PBXs 
via a European-standard 30-channel interface and allows terminals connected to 
a terminal adapter/telephone set to use VMS host services on Ethernet through 
the PBX and its associated building wiring.

The interface between the PBXserver and the PBX runs at 2.048Mbps. It is called 
"ECMA S2" interface, based on the "ISDN primary rate interface, 30B+D", and 
carries 30 data communications simultaneously.  It is fully described by a set 
of ECMA standards, based on CCITT recommendation for ISDN, as listed in 
Appendix A.

The terminal user has to establish a connection to the PBXserver by "dial-in" 
through the terminal adapter/telephone set and the PBX.  Once connected to the 
PBXserver, the user has the same general functionality as a user of the 
DECserver terminal servers and can manage several sessions on several services. 
Note that the "dial-in" procedure is PBX-specific.

The PBXserver also allows for VMS host-initiated connections to asynchronous 
printers. This allows the printers to be distributed throughout a facility 
through the PBX's ports and accessed transparently by service node users. 
Incoming host-initiated connect requests may be queued FIFO at the PBXserver. 

The purpose of using a PBX for terminal access to services on Ethernet is to  
have a higher number of POTENTIAL users than ACTUAL users; a concentration 
factor between 5:1 and 3:1 is reasonable for an office environment.  With 30 
data communications supported by the ECMA S2 link, 90-150 occasional users can 
be supported.

The PBXserver software is down-line loaded into PBXserver hardware from a 
VAX/VAX/VMS host system running DECnet/VAX. Then, users may access 
Ethernet-based MicroVAX VMS host services via LAT protocol.

Two types of user interfaces are provided:

oo   To the terminal user

oo   To the privileged user (system manager)

Terminal User Interface

The user first has to "dial  in" through the terminal adapter/telephone set 
and the PBX. Once the circuit is established, the user enters the LOCAL 
mode of the PBXserver.

In LOCAL mode the user may:

oo   DISPLAY the list of authorized host services and their shortnames

oo   CONNECT to any authorized VMS host service on Ethernet, setting up for 
    each terminal up to 8 sessions at the same time

oo   RESUME a session which has been interrupted by using the BREAK Key

oo   SHOW SESSION list the current sessions

oo   BACKWARD, FORWARD select a session

oo   DISCONNECT from the session

oo   SET and SHOW terminal parameters, and retain them

oo   COMMUNICATE to a host service, once it is connected, through the Local 
    Area Transport (LAT) architecture

oo   Obtain HELP for the user commands

oo   LOGOUT to break the connections with the PBXserver and the PBX

Once connected to a host service, the user is in SERVICE mode. In SERVICE  
mode, the user can work with any application in a transparent manner.  The 
user can interrupt a session with the BREAK Key, create another session or 
DISCONNECT from the current service.

Privileged User Interface

An interface to a privileged operator is provided in order to:

oo   SET and SHOW terminal and printer ports parameters and retain them

oo   SET and SHOW PBXserver parameters, and retain them

oo   SHOW PBXserver statistical informations

oo   DISCONNECT all terminals

oo   PERFORM PBX maintenance functions

oo   MANAGE the PBXserver

oo   DEFINE the line characteristics, service shortnames

oo   Obtain HELP for the privileged commands

Terminal Characteristics

The PBXserver supports the simultaneous operation up to 30 asynchronous  
terminals, including keyboard send-receive (KSR-) printers and PCs.

Printer Characteristics

The PBXserver software support all the DIGITAL asynchronous serial 
(RS-232c) printers when accessed from VMS and MicroVMS systems using 
XON/XOFF protocol.

Additional Features 

oo   XON/XOFF flow control between terminal and the PBXserver.  It can be 
    dynamically enabled or disabled.

oo   Switching to different host services from the LOCAL prompt of the 
    PBXserver  without having to re-dial the connection through the PBX.

oo   Access control by group codes limiting accessibility of certain hosts 
    to terminals.

oo   Direct Inward Dialing through the PBX for fast connection to a host 
    service.

Restrictions On PBXserver Usage

Due to an XOFF maximum delay of 60 ms in the PBXserver, it is recommended 
to  set VT100 terminals to 2400 bps to avoid the risk of data loss.
    
The throughput of the PBXserver may be degraded when the number of host 
services is more than 8 and/or too many terminals or printers work at 19200 
baud. Depending on the configuration, the privileged command DEFINE SERVER 
or SET SERVER allows the user to tune PBXserver by modifying  the maximum 
number of allowed terminals and the maximum number of host services. 

The PBXserver support up to 8 sessions by terminal and up to 6 printers 
queuing up to 40 requests.

INSTALLATION

Only experienced customers should attempt installation of this product. 
DIGITAL recommends that all other customers purchase DIGITAL's Installation 
Services. These services provide for installation of the software product 
by an experienced DIGITAL Software Specialist.

The installation service includes:

oo   Installation of the PBXserver, V2.1 software on one DECnet VAX or 
    MicroVAX host

oo   Configuration of the PBXserver unit on that load host

oo   Configuration of the LAT service node software on one service node

oo   Installation verification and checkout

Customer Responsibilities

Before installation of the software, the customer must:

oo   Previously have installed all prerequisite hardware.

oo   Obtain, install, and demonstrate as operational all other 
    communications   equipment and facilities necessary to interface to 
    DIGITAL's equipment.    This  includes  the equipment  which is the PBX 
    supplier's responsibility, in particular the hardware and software 
    upgrades of the PBX, the telephone  sets  with separate or built-in 
    terminal adapters, and the 2Mbps cable between the PBX and the 
    PBXserver.   Note: The PBX supplier is responsible for soldering the 
    2Mbps cable to the S2 connector of the PBXserver.

HARDWARE REQUIREMENTS

VAX, MicroVAX or VAXstation configuration as specified in the System 
Support Addendum (SSA 29.23.02-x).

SOFTWARE REQUIREMENTS*

MicroVMS Operating System or VMS Operating System 

DECnet-VAX

*   Refer to the Support System Addendum for availability and required 
    versions of prerequisite software (SSA 29.23.02-x).

ORDERING INFORMATION

Software Licenses: QL-VCCE*-**
Software Media: QA-VCCE*-**
Software Documentation: QA-VCCEA-GZ
Software Product Services: QT-VCCE*-**
  
*   Denotes variant fields. For additional information on available 
    licenses, services and media, refer to the appropriate price book.

The above information is valid at the time of release. Please contact your 
local DIGITAL office for the most up-to-date information.

SOFTWARE LICENSING

This software is furnished under the licensing provisions of DIGITAL's 
Standard Terms and Conditions. For more information about DIGITAL's 
licensing terms and policies, contact your local DIGITAL office.

License Management Facility Support

This layered product supports the VMS License Management Facility. License 
units for this product are allocated on a CPU-capacity basis.

For more information on the License Management Facility, refer to the VMS 
Operating System Product Description (SPD 25.01.xx) or the License 
Management manual of the VMS Operating System documentation set.

For more information about DIGITAL's licensing terms and policies, contact 
your local DIGITAL office.

SOFTWARE PRODUCT SERVICES 

A variety of service options are available from DIGITAL. For more 
information contact your local DIGITAL office.

SOFTWARE WARRANTY

Warranty for this product is provided by DIGITAL with the purchase of a 
license for the product as defined in the Software Warranty Addendum of 
this SPD.

                       APPENDIX 

                 LIST OF STANDARDS

          List of ECMA Technical Reports



  TITLE OF DOCUMENT                            ECMA STANDARD         CCITT REC.

1. Interface between Data Processing	        ECMA TR24
   Equipment and PABX

2. Rate Adaption for the Support of		ECMA STD102		V.110
   Synchronous and Asynchronous Equipment
   Using the V.Series Type Interface on a PCSN


3. Specification of the Physical Layer 	        ECMA STD104		I.431
   at the Primary Rate Access Interface
   Between Data Processing Equipment and PCSN

4. Data Link Layer Protocol Specification       ECMA STD105		Q.921
   for the D Channel of the S Interfaces
   Between Data Processing Equipment and PCSN

5. Layer 3 Protocol Specification for 	        ECMA STD106		Q.931
   the Signalling on the D Channel of the
   S Interfaces Between Data Processing
   Equipment and PCSN

6. Technical Report on the Maintenance of       ECMA TR34
   Data Terminal Equipment to PCSN Interfaces
