________________________________________________________________________________
XON "n" Default: $11 <CTRL-Q>
Mode: All Host: XN
_________________________________ Parameters: __________________________________
"n" - 0 to $7F (0 to 127 decimal) specifies an ASCII character code.
________________________________________________________________________________
XON selects the PK-900 Start character that is sent to the computer or
terminal to restart input from that device.
The Start character default value is <CTRL-Q> for computer data transfers.
________________________________________________________________________________
ZFree Immediate Command
Mode: All Host: ZF
________________________________________________________________________________
This command is primarily of interest to HOST mode programmers. ZFREE is an
immediate read-only command that returns the amount of data RAM that is
available in the PK-900. n is the number of free internal memory blocks.
Each memory block holds 28 bytes of data.
Use the ZFREE command to avoid the situation in which a host mode application
sends a block of data to be transmitted, but the controller cannot issue a data
acknowledgement (5F X X 00) to the host computer right away because the TNC is
too full. The application should not send data to the controller if it would
cause the value of ZFREE to drop below 64. To avoid the transmission of RNR
(device busy) packets, the application should make sure ZFREE does not drop
below 128.
Note that ZFREE is different from the FREE command, which shows the number of
message bytes available to the maildrop. (ZFREE times 28 is always larger than
the value of FREE.)
1/93 A-111
Summary of Contents for PK-900
Page 14: ...The rest of this page is blank 3 93 TOC 10 ...
Page 86: ...This page is used to make the number of pages in this chapter an even number 1 93 4 44 ...
Page 114: ...The rest of this page is blank 1 93 6 16 ...
Page 136: ...The rest of this page is blank 1 93 7 22 ...
Page 142: ...The rest of this page is blank 1 93 8 6 ...
Page 178: ...The rest of this page is blank 3 93 11 22 ...
Page 296: ...3 93 6 ...
Page 297: ...APPENDIX B 1 93 B 1 ...
Page 298: ......
Page 299: ......
Page 300: ......
Page 301: ......
Page 302: ...APPENDIX B 1 93 B 2 ...
Page 303: ...APPENDIX B 1 93 B 3 ...
Page 304: ...APPENDIX B 1 93 B 4 ...
Page 305: ...APPENDIX C PK 900 Display Board PARTS PICTORIAL 1 93 C 1 ...
Page 306: ...PK 900 Main Board Logic Section PARTS PICTORIAL 1 93 C 2 APPENDIX C ...
Page 307: ...PK 900 Main Board Logic Section PARTS PICTORIAL 1 93 C 3 ...
Page 308: ...3 93 C 4 ...
Page 309: ......
Page 310: ......
Page 311: ......
Page 312: ...3 93 D 4 ...
Page 318: ...D ...
Page 319: ...D ...
Page 320: ...D ...
Page 321: ...D ...
Page 322: ...D 9 99 E 10 ...
Page 323: ...D ...
Page 326: ...PK 900 Gateway Option Supplement 2 This page intentionally left blank ...
Page 351: ...27 PK 900 Gateway Option Supplement This page intentionally left blank ...
Page 352: ...PK 900 Gateway Option Supplement 28 ...
Page 365: ...TNC GPS Upgrade Addendum 13 13 13 13 13 ...
Page 369: ......
Page 370: ...Figure B REMOVE VIA ...
Page 373: ...1 PK 900 PSK Sound Card Interface Upgrade Kit A 06265 Installation and Operation Manual ...
Page 383: ...11 ...
Page 384: ...12 ...
Page 389: ...17 Section 5 PK 900 PSK Sound Card Interface Schematic Diagrams ...
Page 392: ......