1001 Category 2, Type A - X.25 Packet Switched BSA

Category 2 - Packet Switched Basic Serving Arrangement

A packet switched (BSA) provides an ESP with a connection to the packet switched
network.  This BSA is capable of supporting analog or digital signals of various
transmission rates.  The transmission interface may be 2-wire or 4-wire, or
derived from a variety of multiplexing alternatives (e.g., DS-1 or DS-3).

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Category 2, Type A - X.25 Packet Switched BSA

The Type A Packet Switched BSA provides an ESP with X.25 access to the BOC 
packet switching network.  This interface conforms to CCITT Recommendation X.25.

X.25 supports physical, link and packet level procedures.  At the physical
level, data signaling rates of 1.2, 2.4, 4.8, 9.6 and 56 kbps are supported.
The link level protocol supported at the interface is LAPB procedures.  The 
main function of the link level protocol is to ensure that the packets cross 
the DTE/DCE interface essentially error free.  The network level access protocol
provides the procedures required to set up, maintain and clear virtual calls.

Generic Name of BSA
 	Regional Company BSA Name
==========================================================================
Category 2, Type A - X.25 Packet Switched BSA
	AM - Packet Switched (X.25)
     	BA - Public Data Network: X.25
     	BS - PulseLink(R) Packet Switching - X.25
     	NX - Packet Switched - Line
     	PB - Public Packet Switching (X.25)
     	SWB - Packet Switched - MicroLink II(sm) (X.25 Version)
     	USW - Packet Switching (X.25)

References:  PPSNGR TR-TSY-301 Public Packet Switched Network Generic
Requirements, Issue 2, December 1988.  TR-TSY-000462 Public Packet
Switched Network (PPSN) X.25 Interface Description, Issue 1, June 1987.
TR-NPL-000011 Asynchronous Terminal and Host Interface Reference, Issue 1, 
March 1985.  
Ameritech TR-NPL-000001 Public Packet Services Technical Interface 
Specifications, Issue 1, December 1985.  Ameritech TR-NPL-000002 
Technical Interface Specifications for X.25 Service, Issue 2, May 1988. 
Ameritech TR-NPL-000003 Technical Interface Specifications for Asynchronous 
Service, Issue 2, May 1988.  Ameritech TR-NPL-000007 Digital Service Interface 
Specifications, Type 1, Issue B, December 1988.  
Bell Atlantic TR 72211 Interface Specification For The Bell Atlantic Public 
Data Network, November 1987.  
BellSouth TR-73513 PulseLink(R) X.25 Interface Specification, June 
1987.  BellSouth TR-73516 PulseLink(R) Physical Interface Specification, 
Issue B, December 1988.  
NYNEX NTR-74250 Infopath(sm) Packet Switching Service X.25 Interface 
Specification, Issue 2, January 1988.  NYNEX NTR-74252 Infopath(sm) Packet 
Switching Service Asynchronous Interface Specification, Issue 2, January 1988.
Pacific Bell PUB L-780060-PB Public Packet Switching (PPS) - Technical 
Interface Specification, Issue 1, August 1989.  
Southwestern Bell Telephone Technical Publication TP 76800, MicroLink II 
X.25/X.75 Reference, Issue 2, January 1990.  Southwestern Bell Telephone 
Technical Publication TP 76810, MicroLink II Asynchronous Reference, Issue 2, 
January 1990.
U S WEST USWTR 77359 DIGIPAC(sm) Packet Switching Interface Specifications, 
April 1988.

MicroLink II is a registered service mark of Southwestern Bell Telephone.
PulseLink is a registered trademark of BellSouth.
DIGIPAC is a service mark of U S WEST.
