digital equipment corporation · maynard, massachusetts
R and S Serial Discrete Transistor Logic Boards

The R and S series FLIP-CHIP boards were used in the original PDP-8 introduced in 1965 and peripherals. The R series was also sold as building blocks for custom hardware. They replaced the original product of Digital Equipment Corporation (DEC) which was the System Modules. The system modules were used to make the PDP-5 which was the predecessor of the PDP-8. The R series boards were replaced by the M series logic using standard TTL logic IC's when IC's became common and affordable. The M series board were first listed in the 1968 logic handbook and used in the PDP-8/I introduced in 1968. The S series boards are identical to the R series boards except lower resistance pulldown on output. This gave them higher speed but reduced fanout capability. Some also had coupling capacitor and other resistor value changes. More R/S series information. The R series logic is explained in this document and the earlier logic handbooks available here.

The R and S series boards have Red handles.

R Series Features:

The following picture links also have descriptions of what is shown in the pictures.

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Discrete transistor logic boards. All these board are made from discrete transistor and diodes, no IC's

Gates and Registers/Flip Flops

R002 Diode Network ( 19K)  back of board ( 20K)
R107 Inverter ( 29K)  back of board ( 38K)
R111 Expandable NAND/NOR gate ( 24K)  back of board ( 33K)
R113 NAND/NOR Gate ( 28K)  back of board ( 37K)
R123 Input Bus Gate ( 27K)  back of board ( 33K)
R151 Binary to Octal Decoder ( 52K)  back of board ( 54K)
R181 DC Carry Chain ( 40K)  back of board ( 46K)
R202 Dual Flip Flop ( 32K)  back of board ( 44K)
R203 Triple Flip Flop ( 34K)  back of board ( 47K)
R205 Dual Flip Flop ( 36K)  back of board ( 45K)

Delays, Multivibrators and Oscillators

R302 Dual Delay (One Shot) ( 35K)  back of board ( 47K)
R303 Integrating One Shot ( 31K)  back of board ( 42K)
R401 Rev D Variable Clock ( 28K)  back of board ( 35K)  R401 Rev H Variable Clock ( 28K)  back of board ( 40K)
R405 Crystal Clock ( 31K)  back of board ( 36K)

Pulse Amplifiers

R602 Dual Pulse Amplifier ( 31K)  back of board ( 44K)
R603 Triple Pulse Amplifier ( 32K)  back of board ( 45K)

Feel free to contact me, David Gesswein djg@pdp8online.com with any questions, comments on the web site, or if you have related equipment, documentation, software etc. you are willing to part with.  I am interested in anything PDP-8 related, computers, peripherals used with them, DEC or third party, or documentation. 

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