Register Description
C/R
Command/Response
The C/R bit identifies a receive frame as either a command or a response, according
to the LAPD rules:
Command
Response
Direction
0
1
1
0
Subscriber to network
Network to subscriber
4.1.16 SAPI2 Register
SAP2
Write
Address 27
H
7
0
SAPI1
SAPI2
MCS
0
SAPI2 SAPI2 Value
Value of the second programmable Service Access Point Identifier (SAPI) according
to the ISDN LAPD protocol.
MCS
Modulo Count Select
Used in auto-mode only.
This bit determines the HDLC control field format as follows:
0: One-byte control field (modulo 8)
1: Two-byte control field (modulo 128)
4.1.17 TEI1 Register 1
TEI1
Write
Address 28
H
7
0
TEI1
EA
EA
Address field Extension Bit
This bit has to be set "1" according to HDLC/LAPD.
In all message transfer modes except in transparent modes 2 and 3, TEI1 is used by
the ISAC-S for address recognition. In the case of a two-byte address field, it contains
the value of the first programmable Terminal Endpoint Identifier according to the
ISDN LAPD protocol.
In the auto-mode with a two-byte address field, numbered frames with the address
SAPI1-TEI1 are handled autonomously by the ISAC-S according to the LAPD
protocol.
Semiconductor Group
214
INFINEON [ Infineon ]
