IBM 2790, Manual

Page: 31 / 88

Configuration Parameters
The configuration parameters are specified by the customer
and inserted by the customer engineer at the time of
installation. These parameters are:
• 50/60 Hz power
• Internal/external Real-Time Clock advance
• 12/24-Hour Real-Time Clock display
• System error threshold
• Half/full-duplex data set
• Internal/external BSC clock
• Switched/nonswitched/multipoint lines
• Primary/secondary stations
• BSC retry count
• Station ID (up to 15 EBCDIC characters)
• System ID (up to 15 EBCDIC characters)
• Poll address (2-7 Graphics)
• Selection address (2-7 Graphics)
• Originate/called station
• Intermediate/Non-intermediate block check mode
• Normal/Expanded Capability
• Time Out (for Stop 2790 Input)
• Area Station Error Threshold
2715 G E N E R A L C H A R A C T E R IS T IC S
Multiplexer Channel Adapter (Standard on 2715 Model 1)
The Multiplexer Channel Adapter (MCA) establishes and
maintains communication with the processor channel while
performing control functions and data transfers. To the
multiplexer channel, the MCA looks the same as the 2701
Data Adapter Unit.
The adapter handles all sequencing, command and
instruction buffering, and data and status transfer via hard­
ware.
Command Compatibility (2715/2701)
Compatible. Usage of the following commands is compatible
between the 2715 and the 2701:
Read
Write
Prepare
Sense
No-Op
Test I/O
Enable
Disable
Set Mode
Release
Reserve
N ot Compatible. The 2715 does not use the following
commands used by the 2701:
Dial
Poll
Search
Address Prepare
These commands are rejected by 2715 at “initial selec­
tion.”
Sense Byte
Sense Bits Used. The 2715 uses the following sense bits:
Command Reject
Bus-Out check
Equipment check
Lost Data
Timeout
The Timeout in the 2715 local configuration is immediate.
Sense Bits N ot Used. The 2715 does not use the following
sense bits used in the 2701:
Intervention Required
Data Check
Overrun
These conditions cannot occur in the 2715; therefore, these
bits are not used.
Status Byte
Status Bits Used. The 2715 uses the following status bits:
Channel End
Device End
Unit Check
Unit Exception
Busy
Status Bits N o t Used. The 2715 does not use the following
status bits:
Attention
Status Modifier
Initial Selection
Initial-selection sequences are generated from execution of
an I/O instruction or command chaining within the channel.
The 2715 responds to initial selection with the following
exceptions:
1. Power down
2. Off line mode (inactive)
| 3. 2715 Hard stops
IBM 2715 Transmission Control Unit 31