Epson Multi-mode Data Controller MFJ-1278B Benutzerhandbuch

The MFJ-1278B has a built-in TTL-level port for interfacing with the Commodore C64, 
C128 or the VIC-20 computers.  You do not need a RS-232C converter to interface with the 
MFJ-1278B. 
 
An optional Starter Pack for the C-64, C-128 or the VIC-20 is available from MFJ 
Enterprises, Inc. or any dealer of MFJ products.  The Starter Pack includes a cable from the 
MFJ-1278B TTL port to the user I/O port on the Commodore computer.  Included also is a 
terminal program.  To order, specify MFJ-1282B for software on disk or MFJ-1283 for 
software on tape.  If you wish to construct your own cable, the information below in Figure 2-
2A will be helpful: 
 

1 

RXD 

Receive Data 

B,C 

2 

DCD 

Data Carrier Detected 

H 

3 

GND 

Ground (Frame and Signal) 

N 

4 

RTS 

Ready To Send 

E** 

5 

TXD 

Transmit Data 

M 

6 

DSR 

Data Set Ready 

L 

7 

CTS 

Clear to Send 

K 

  *C-128 is used in the C-64 mode for these connections. 
 
  **Pin E is not needed when using terminal program referred to in this chapter for the 
Commodore computers. 
 
The TTL port (J5), is numbered from left to right as viewed from the back panel of the MFJ-
1278B.  The user's terminal program may not use all of these connections.  The MFJ-1278B 
requires RXD, TXD and GND connected for proper operation.  Programs that utilize file 
transfer and printer routines will probably use RTS and CTS as well.  Consult your software 
documentation. 

The PCjr uses standard serial voltage levels for it's RS-232C interface; however, the 
connector used is non-standard and not readily available from electronic supply dealers.  The 
pin-out information for this connector is refered to in the IBM  PCjr  Technical  Reference 
Manual. 
 
IBM dealers sell an "IBM PCjr Adapter Cable for Serial Devices".  This Adapter Cable is