Service manual

REVISION SUMMARY
C-2
April 2001
Part No. 001-9800-203
C.3 TUNING SOFTWARE REVISIONS
The operation of the tune software is described in
Section 7. Recent revisions to this software are as
follows:
Version 203 - Released 8/99
• Added the capability to tune the RSSI-enhanced
squelch used by transceivers having the upgraded
squelch circuit and running Version 209 or later
software (see Sections C.1 and C.4).
NOTE: This version or later must be used to tune
upgraded transceivers running operating software
Version 209 or later (see Sections C.1 and C.3)
Version 202 - Released 3/98
• Added capability to tune 800 and 900 MHz models
C.4 REVISION LETTER CHANGES
3.4.1 GENERAL
The transceiver revision letter is changed when-
ever a major hardware or software change occurs. The
revision letter is part of the transceiver identification
number described in Section 1.4. Each 98xx model can
have a unique revision letter, and the part numbers
used to identify the various models are described in
Section 1.3.
3.4.2 SQUELCH CHANGE
Table C-1 lists the revision letter change that
occurred when hardware and logic changes were made
that allowed an improved squelch algorithm to be
used. This algorithm utilizes both noise and RSSI
signals similar to LTR-Net models, and is used if the
transceiver has these hardware changes and Version
209 or later operating software (see Section C.1).
NOTE: To tune an upgraded transceiver running
Version 209 or later operating software, tuning soft-
ware Version 203 or later, must be used (see
Section C.3).
The following are the squelch and RSSI circuit
changes that occurred when the revision letter change
in Table C-1 occurred:
Audio/Logic Board Changes
C304 - .22µF to .033µF
R300 - 15k to 6.8k
R301 - 10k to 4.7k
R302 - 1k to 680
R305 - 270k to 390k
R307 - 10k to 5.6k
R310 - 270k to 150k
R143 - 1k to 2.7k
R161 - 10.5k to 24.3k
R197 - 10k (added)
RF Board Changes
R258 - 3.3k to 10k
C303 - .01µF to .33µF
3.4.3 LTR-NET UPGRADABLE MODELS
With high tier models only, the revision letter
change in Table C-1 also indicates which transceivers
are field upgradable to LTR-Net operation. Earlier
models can also be upgraded, but they must be
returned to the factory for the squelch circuit and logic
changes. Field upgrading is performed using special
software and keys purchased from the E.F. Johnson
Company. Low tier models are not capable of LTR-
Net operation and therefore are not field upgradable.
Table C-1 Revision Letter of Upgraded
Models
Model
Revision
Letter
Model
Revision
Letter
9841-232 J 9881-203 D
9841-233 F 9881-802 C
9841-252 J 9883-202 E
9843-232 D 9883-203 E
9843-233 D 9894-202 D
9843-252 K 9894-203 D
9843-253 J 9896-202 D
9881-202 D 9896-203 D
NOTES:
1. The model is indicated by the last seven digits of the
transceiver part number (see Section 1.3).
2. Models with the above revision letter or later have
been upgraded.