588
Chapter 25, Modifications, Accessories, Manuals, Support
Modifications
Firmware Upgrades
a. Option 004 Tone/Digital Signaling.
b. For HP8920A/21A with S/N < 3546A and
includes R98.
c. For HP8920A/21A with S/N ≥ 3456A.
Table 15 Firmware Upgrades
Description HP 8921A
Operating System and Signaling
a
ROMs R40
b
R98
c