The LH-DH/11 Local/Distant Host Controller is a DMA UNIBUS 1822 interface produced by ACC to allow a UNIBUS machine to connect to anything that provided a BBN-1822 bit-serial interface; most commonly as IMP interfaces to ARPANET IMPs, but also to Packet Radio Network interfaces.
It consists of a 10-1/2" rack mounting box holding a pair of wire-wraped boards (one for packet input, and one for output), holding a number of SSI TTL integrated circuits; there is also an internal power supply. Level converters allow use as either a Local Host or Distant Host 1822 interface; BC11A cables connect it to the rest of the system.
Registers
| Register |
Abbreviation |
Address
|
| Control & Status In Register |
CSRI |
0767600
|
| Data Buffer In Register |
DBRI |
0767602
|
| Current Word Address In Register |
CWAI |
0767604
|
| Word Count In Register |
WCI |
0767606
|
| Control & Status Out Register |
CSRO |
0767610
|
| Data Buffer Out Register |
DBRO |
0767612
|
| Current Word Address Out Register |
CWAO |
0767614
|
| Word Count Out Register |
WCO |
0767616
|
0767600: Control & Status In Register (CSRI)
| ERR |
NXM |
EOM |
Unused |
HR |
INR |
RMRE |
IDBF |
RDY |
IE |
XBA16-17 |
SENB |
HRC |
IRST |
GO
|
| 15
|
14
|
13
|
12
|
11
|
10
|
09
|
08
|
07
|
06
|
05
|
04
|
03
|
02
|
01
|
00
|
- ERR - Error Flag
- NXM - Non-Existent Memory
- EOM - End of Message
- HR - Host Ready
- INR - IMP Not Ready
- RMRE - Receive Master Ready Error
- IDBF - Input Data Buffer Full
- RDY - Device Ready
- IE - Interrupt Enable
- SENB - Store Enable
- HRC - Host Relay Control
- IRST - Input Interface Reset
0767602: Data Buffer In Register (DBRI)
| Data15 <---> Data00
|
| 15
|
14
|
13
|
12
|
11
|
10
|
09
|
08
|
07
|
06
|
05
|
04
|
03
|
02
|
01
|
00
|
0767604: Current Word Address In Register (CWAI)
| WA15 <---> WA00
|
| 15
|
14
|
13
|
12
|
11
|
10
|
09
|
08
|
07
|
06
|
05
|
04
|
03
|
02
|
01
|
00
|
0767606: Word Count In Register (WCI)
| WC15 <---> WC00
|
| 15
|
14
|
13
|
12
|
11
|
10
|
09
|
08
|
07
|
06
|
05
|
04
|
03
|
02
|
01
|
00
|
0767610: Control & Status Out Register (CSRO)
| ERR |
NXM |
WC0 |
Unused |
TMRE |
ODBE |
RDY |
IE |
XBA16-17 |
BBM |
ELB |
ORST |
GO
|
| 15
|
14
|
13
|
12
|
11
|
10
|
09
|
08
|
07
|
06
|
05
|
04
|
03
|
02
|
01
|
00
|
- ERR - Error Flag
- NXM - Non-Existent Memory
- WC0 - Word Count = 0
- TMRE - Transmit Master Ready Error
- ODBE - Output Data Buffer Empty
- RDY - Device Ready
- IE - Interrupt Enable
- BBM - Bus-Back Mode
- ELB - Enable Last Bit
- ORST - Output Interface Reset
0767612: Data Buffer Out Register (DBRO)
| Data15 <---> Data00
|
| 15
|
14
|
13
|
12
|
11
|
10
|
09
|
08
|
07
|
06
|
05
|
04
|
03
|
02
|
01
|
00
|
0767614: Current Word Address Out Register (CWAO)
| WA15 <---> WA00
|
| 15
|
14
|
13
|
12
|
11
|
10
|
09
|
08
|
07
|
06
|
05
|
04
|
03
|
02
|
01
|
00
|
0767616: Word Count Out Register (WCO)
| WC15 <---> WC00
|
| 15
|
14
|
13
|
12
|
11
|
10
|
09
|
08
|
07
|
06
|
05
|
04
|
03
|
02
|
01
|
00
|
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