Byte Back MD-2B modem
Order from:
Byte Back Co.
Rt. 3, Box 147, Brodie Road
Leesville, S.C. 29070
$149.95 (A&T)
$119.95 (KIT)
add $4.95 for shipping and handling
(803) 532-5812
The Byte-Back MD-2B is an excellent choice for a modem for the Timex Sinclair computers. It plugs right onto the back of the 1000, 1500, and ZX81 computers. There is an extra kit you can buy that adapts the MD-2B to the TS 2068. It is an additional $19.95.
Byte-Back has been making modems for the Timex Sinclair 1000/ZX81 for over a year, and their newest modem is great. It even beats the Timex 2050 modem. You may think not, because you can get the 2050 modem for only $119.95, but the Byte-Back modem includes a down/uploading program and a free serial printer port, both of which the 2050 does not have (the downloading program will cost $19.95 for the 2050 if, and when, it comes out, so that alone brings the price right up to the MD-2B). The MD-2B does not have auto dial/answer like the 2050, and they are not really that important. Auto answer is not needed at all, since if you leave the computer on, it will answer the phone everytime it rings, and that can be a nuisance. I also think the MD-2B has a much better terminal program for the 1000. With the MD-2B’s terminal program (Z-COMM), you can send and see an apostrophe, brackets, the “#” sign, and the “@” sign, all of which just show up as inverse grey spaces on the 2050’s terminal program for the 2050, and they can’t be sent (obviously).
The control characters on the MD-2B are sent very easily. You send them as if they were inverse characters. For instance, if you want to send a control “h” (a backspace), you would do the following: hold “SHIFT” down, press “9” (like you do to get into graphics mode) and press the “H” key. When you hit SHIFT 9, instead of the cursor being an inverse “G”, it’s an inverse “C”, (for “CONTROL”). Z-COMM is available in a 2K and 16/64K version allows you to upload/download, and with 64K, there is a thing called “UPPER MEMORY FUNCTION” (it allows you to store programs and data in the upper 32K of memory when regular BASIC space gets full).
The printer port is serial and it’s memory mapped. This means you can access it in BASIC using POKEs. If you want to buy a program so you can use LLIST, LPRINT, and COPY, Byte-Back sells one. The port also adjusts to the baud rate of the printer, (and that also means the modem can too).
The modem does not operate only at 300 BAUD, but 50-19500 BAUD (the Timex can only handle up to 2400 BAUD without going nuts, and even at that rate, there are lots of errors). So the modem can operate at higher than 300 BAUD, the host computer has to be sending at a higher rate than 300 BAUD. THERE IS NO CONTROL TO SEND AT A CERTAIN BAUD RATE…THE HOST HAS TO BE SENDING AT THAT RATE FOR THE MODEM TO OPERATE AT HIGHER THAN 300 BAUD!
I very highly recommend the MD-2B. It is an excellent modem, and you will find that telecommunications is a great hobby. I sure did, and with the free serial printer port, the MD-2B is an exceptional value.
If you have any questions about the MD-2B, call me at [phone number omitted] (mst).