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MFJ-1278B MULTI-MODE HARDWARE
HARDWARE
This chapter details the specifications and the functional description of the MFJ-1278B
hardware design.
MFJ-1278B SPECIFICATIONS
Processor
CMOS Z-80A
Clocks
Processor master clock input frequency: 4.9152 MHz
User Port Clock:
Switch selectable at 16x baud rate.
Memory
All memory in industry-standard JEDEC Byte-Wide sockets.
Standard complement of ROM: 1 Megabit (128K x 8) 1 x 27C101
Standard complement of system RAM: 32K 1 x 43256C-15L
Standard complement of mailbox RAM: 32K (expandable to 512K)1 x 43256C-15L
Serial Port
A Z8440 SIO/0 type device, port B configured as UART plus low- Portpower TTL-to-
RS-232C signal level interface.
Baud rates supported: 300, 1200, 2400, 4800, 9600 and 19,200.
Standard female DB-25S (DCE) RS-232C connector. An 8-pin molex male connector
for TTL serial port.
Modem
Demodulator: XR2211 PLL demodulator circuit plus related components to receive up
to 1200 baud.
Modulator: XR2206 modulator circuit plus related components to produce tones for all
modes of operation.
Built-in modem calibration system.
An external modem may be attached by a single connector which completely bypasses