PEB2085 SIEMENS [Siemens Semiconductor Group], PEB2085 Datasheet - Page 214

• Manufacturer Part Number: PEB2085
• Description: ISDN SubscribernAccess Controller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Semiconductor Group
C/R
4.1.16
SAPI2
MCS
4.1.17
EA
7
Command/Response
The C/R bit identifies a receive frame as either a command or a response, according
to the LAPD rules:
7
Value of the second programmable Service Access Point Identifier (SAPI) according
to the ISDN LAPD protocol.
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)
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.
SAPI2 Value
SAPI2 Register
TEI1 Register 1
Command
0
1
SAPI1
Response
1
0
SAPI2
TEI1
214
SAP2
TEI1
Direction
Subscriber to network
Network to subscriber
Write
Write
MCS
Register Description
EA
0
Address 27
Address 28
0
0
H
H