PacComm TINY-2 Product manual

TECHNICAL REFERENCE MANUAL
for
PacComm Packet Controller Models
TINY-2 and MICROPO ER-2

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
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TABLE OF CONTENTS
INTRODUCTION ............................................................................... 4
Fea ures ................................................................................ 4
NET/ROM and ROSE Compa ibili y ........................................... 4
COMPUTER INTERFACING ................................................................. 5
RS-232 Por Signals ................................................................ 5
Nons andard RS-232C Serial Por s ........................................... 6
Serial Por Opera ion A TTL Levels .......................................... 7
Serial Da a Signal Defini ions .................................................. 7
RS-232C Handshaking Pro ocol ................................................ 9
RADIO INTERFACING ........................................................................ 10
Radio Connec or (J2) Pin Defini ions ........................................ 10
Direc Connec ion o Microphone and Speaker .......................... 10
Accessory Jack Connec ion ...................................................... 11
Ex ernal In erface Box ............................................................ 11
HARDWARE DESCRIPTION ................................................................ 12
LEDs ..................................................................................... 12
De ailed Circui Descrip ion ..................................................... 12
Modem Disconnec - J5 ........................................................... 13
ADJUSTMENTS ................................................................................. 16
Jumper Func ions ................................................................... 16
JP B: Li hium Ba ery .................................................... 16
JP D: NET/ROM + RFDCD ............................................. 16
JP L: Digi al Loopback .................................................. 16
JP RA: Audio Inpu Impedance ..................................... 16
JPAux: Auxiliary I/O ..................................................... 16
JP 8: Power Connec ion ................................................ 16
Trimpo /Varicap Adjus men s .................................................. 16
Baud Ra e Se ing .................................................................. 16
Audio Inpu Level ................................................................... 17
Transmi Level Se ing ............................................................. 17
Modem Receive Bias Adjus men ............................................. 18
Carrier De ec Level ................................................................ 18
Crys al Oscilla or Adjus men .................................................. 18
TROUBLESHOOTING ......................................................................... 19
Loopback es ing .................................................................... 20
Analog loopback .......................................................... 20
Digi al loopback ........................................................... 20
General Tes s ......................................................................... 20
S ep 1: Obvious Problems ............................................. 20
S ep 2: Power Supply ................................................... 21
Compu er Terminal In erface .................................................. 21
Packe Con roller won' sign on o he Compu er ............ 21
The Con roller prin s only gibberish ............................... 21
The Con roller won' accep commands ......................... 22

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
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O her Symp oms .................................................................... 22
TINY-2/MICRO-2 appears dead ..................................... 22
Modem won' key ransmi er ........................................ 22
Uncopyable ransmi ed packe s .................................... 22
Uncopyable received packe s ........................................ 23
DCD LED flickers excessively or s ays on ........................ 23
Transmi er locks in ransmi condi ion ........................... 23
APPENDICES
Node In erconnec ion Cables .................................................. 24
Dual TINY-2/MICRO-2 Node .......................................... 24
Dual Node, TINY-2/MICRO-2 and TNC-2(00) .................. 24
Triple Node .................................................................. 24
Compu er In erfacing Diagrams ............................................... 25
Radio In erfacing Diagrams ..................................................... 26
RS-232 Signal Table ................................................................ 27
Bi -Shif ed ASCII Charac er Table ............................................. 28
Schema ic .............................................................................. 29

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
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INTRODUCTION
This manual applies o bo h he TINY-2 and MICROPOWER-2 packe con rollers. These uni s share
he same basic design and in erface o radios and compu er erminals iden ically. The erm TINY-
2/MICRO-2 is used hroughou his manual o refer o bo h uni s when dealing wi h componen s
and procedures which are he same for bo h uni s.
The erms "Compu er and erminal" are used in erchangeably o refer o he compu er or erminal
used o communica e wi h he packe con roller. This is no mean o imply ha a compu er is nec-
essary for opera ion of a packe con roller.
Every effor has been made o make his manual comple e and accura e, however PacComm as-
sumes no responsibili y for damages incurred as a resul of using his documen a ion. PacComm
reserves he righ o make changes o equipmen specifica ions or documen a ion a any ime
wi hou no ice or obliga ion o previous purchasers. Your commen s and sugges ions for improve-
men are welcome.
Be sure o read any erra a, manual upda es, and sof ware release no es before opera ing he pack-
e con roller.
Features
Firmware
Comple ely TNC-2 firmware Compa ible
Suppor s all 'TAPR' commands plus many PacComm addi ions.
Personal Message Sys em (op ional on TINY-2)
Hardware
NMOS Z-80 CPU and SIO (MDLC) [MICROPOWER-2: CMOS]
4.9 MHz CPU clock speed
32k EPROM and 32k RAM
Typical Power Consump ion: 9 – 14 VDC @ 220 mA [40 mA]
Crys al con rolled IC modem suppor s 1200/2200 Hz ones
DE-9P (male) for RS-232 Compu er
TNC-2 ype modem disconnec header
Power, Connec , S a us, PTT, Carrier De ec LEDs
Ex ruded aluminum case 5 × 7 × 1 3/8 inches wi h gray, oven baked wrinkle finish
Me al end panels grounded o preven RFI
MICROPOWER-2 prin er por and hardware clock op ions
NET/ROM and ROSE Compatibility
The TINY-2/MICRO-2 are TNC-2 compa ible meaning ha an EPROM designed for a TNC-2 com-
pa ible (such as bo h NET/ROM and ROSE ne working EPROMs) will opera e in a TINY-2/MICRO-2.
Please refer o Appendix A for in erconnec ion cable Informa ion for dual/mul i-node uni s.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
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COMPUTER INTERFACING
The TINY-2/MICRO-2 packe con roller communica es wi h he compu er or erminal hrough a se-
rial por using ei her RS-232C or "TTL" level signals. One of hese signal levels should properly in-
erface o mos compu ers. See he Appendices o his manual for specific compu er in erfacing in-
s ruc ions.
RS-232 Port Signals
The serial por connec ors on he TINY-2/MICRO-2 packe con roller are on he rear panel marked
"RS-232" and "TTL Compu er". The pins on he serial por connec or of packe con roller ha mus
be connec ed are shown in he following able. This is commonly called a " hree-wire" RS-232 ca-
ble.
RS-232 Serial Por "3 Wire" Cable Wiring for DB-25
Compu er DB-25 TINY-2/MICRO-2
1 and 7 –––––––– 5
2 ––––––––––––– 3
3 ––––––––––––– 2
RS-232 Serial Por "3 Wire" Cable Wiring for DE-9
Compu er DE-9 TINY-2/MICRO-2
5 and Shell ––––– 5
2 ––––––––––––– 2
3 ––––––––––––– 3
The packe con roller is configured as Da a Communica ions Equipmen (DCE), he echnical erm
for an RS-232C modem. Mos compu ers and erminals are configured as Da a Terminal Equipmen
(DTE). Specifically, he packe con roller connec or is an IBM "AT s yle" using a male DE-9 connec-
or, wired as DCE ra her han DTE. If you use an "AT" PC or por able Compu er wi h a 9-pin serial
por , you can wire cable connec or pins 2 hrough 8 direc ly (pin 2 o pin 2, e c.).
Pin 1 on he TINY-2/MICRO-2 is he Da a Carrier De ec (DCD) signal which goes high ( rue) when
he packe con roller is in he "connec ed" s a e. This is analogous o he DCD signal on elephone
modems, i.e. he pin is asser ed when a communica ion connec ion exis s. Pin 9 is used as an aux-
iliary radio carrier de ec inpu . This pin may also be used when wo or more packe con rollers are
ma ed for use wi h ne work firmware such as he NET/ROM or ROSE EPROM. More de ailed infor-
ma ion is presen ed la er in he manual.
Some compu ers require ha Clear To Send (CTS) of he compu er serial por connec or (pin 5 of a
DB-25 or pin 8 of a DE-9) be connec ed o an appropria e signal. O hers may require connec ions
for Da a Carrier De ec (DCD) (pin 8/pin 1) and Da a Terminal Ready (DTR) (pin 20/pin 4). You
may jumper he compu er's inpu and ou pu signals on DB-25 pins 4/5 (DE-9 pins 7/8), and on
DB-25 pins 6/8/20 (DE-9 pins 6/1/4) in addi ion o he connec ions shown in he "3 wire" RS-232
diagram above, or build an "8 wire" in erface cable as shown below:
Jumpering RTS/CTS and DTR/DSR/DCD at the Computer Gable End
DB-25: DE-9:
4 –––––– 5 7 –––––– 8
6 –––––– 8 –––––– 20 1 –––––– 4 –––––– 6

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
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"Eight-wire" RS-232 Cable
Compu er DB-25 or DE-9 o TINY-2/MICRO-2 DE-9P
1 –––––––– Shell –––––––– 5
2 ––––––––– 3 –––––––––– 3
3 ––––––––– 2 –––––––––– 2
4 ––––––––– 7 –––––––––– 7
5 ––––––––– 8 –––––––––– 8
6 ––––––––– 6 –––––––––– 6
7 ––––––––– 5 –––––––––– 5
8 ––––––––– 1 –––––––––– 1 "connec ed" signal
20 –––––––– 4 –––––––––– NC
Non-Standard RS-232C Serial Ports
NOTE: Some compu ers which require an ex ernal TTL o RS-232 adap er o suppor an RS-232 se-
rial por may be in erfaced o he TINY-2/MICRO-2 wi hou he RS-232 adap er uni by using he
TINY- 2/MICRO-2 TTL level signals.
Compu ers wi h non-s andard RS-232 serial por s mus mee he following condi ions:
Vol age levels sen by he compu er mus be grea er han +3 Vol s in one s a e and less han
-3 Vol s in he o her s a e.
The polari y of he signals mus conform o he RS-232C s andard, i.e. he low vol age s a e is
a logical "1" and he high vol age s a e is a logical "0".
Make or buy a cable ha provides he following connec ions:
The compu er serial por common (ground) pin mus be ied o he TINY-2/MICRO-2 serial por
connec or pin 5.
The signal line ha sends da a from he compu er mus be ied o he TINY-2/MICRO-2 con-
nec or pin 3.
The pin on which he compu er receives da a mus be ied o he TINY-2/MICRO-2 connec or
pin 2.
The documen a ion provided wi h he compu er or i s accessory serial por should clarify any re-
quiremen s for addi ional signals.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
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Serial Port Operation At TTL Levels
The TINY-2/MICRO-2 packe con roller is designed o opera e wi h compu ers which have a TTL
level serial por wi hou requiring he use of an RS-232C adap er. This includes such popular com-
pu ers as he Commodore VIC-20, C-64, and C-128. TTL signals are rou ed hrough an 8 pin con-
nec or on he rear panel. TTL signal levels mus be grea er han +2.4 Vol s in one s a e and less
han +.4 Vol s in he o her s a e.
Use cau ion in connec ing he TTL cable o insure ha pin one of he cable is a ached o pin one
of he connec or. Pin one is clearly marked on he rear panel of he con roller. Pin one of he cable
connec or is marked wi h a red s ripe, Be sure o observe his marking bo h in cons ruc ing and a -
aching he cable.
TTL serial port signals used by the TINY-2/M1CRO-2 controller.
P3
Signal Name
Descrip ion
1
2
3
4
5
6
7
8
Receive Da a
Carrier De ec
Frame Ground
Clear o send
Transmi Da a
Signal Ground
Reques o send
No Connec ion
Serial da a to compu er from he TlNY-2/MICRO-2
Goes high when connec ion exis s
Common ground for case and da a lines
Compu er Signal Clearing Con roller o send da a
Serial da a to he TINY-2/MICRO-2 from compu er
Common ground for bo h da a lines and case
Con roller signal o compu er when da a is ready
Serial Data Signal Definitions
This sec ion describes he pins used on he packe con rollers serial por connec ors. Since he pins
are defined wi h respec o he Da a Terminal Equipmen (DTE) (compu er) end of he circui , and
he packe con roller is wired as Da a Communica ions Equipmen (DCE) (modem), some s andard
pin names appear o be he reverse of he packe con roller func ion. A comple e RS-232 signal a-
ble appears in he Appendices.
Serial Port Pin Functions
Frame Ground (FG) is provided for a achmen o he chassis of he packe con roller and he
chassis of he a ached compu er erminal. This is common o he signal ground on he TINY-
2/MICRO-2.
Transmi Da a (TXD) is an inpu line o he packe con roller on which he a ached compu er
erminal device sends da a.
Receive Da a (RXD) is an ou pu line from he TINY-2/MICRO-2 on which i sends da a o he
a ached compu er erminal device.
Reques o Send (RTS) is an inpu o he packe con roller signaling ha he a ached compu -
er erminal device is ready o accep da a from he TINY-2/MICRO-2. This line is used for hard-
ware flow con rol.
Clear To Send (CTS) is an ou pu from he packe con roller signaling he a ached compu er
erminal device o send da a o he TINY-2/MICRO-2. This line is used for hardware flow con-
rol.
Da a Se Ready (DSR) is an ou pu from he packe con roller elling he a ached compu er
erminal device ha he packe con roller is opera ional. On he TINY-2/MICRO-2 his pin is
ied high (ready).
Signal Ground (SG) is he common, or re urn, pa h for all signals be ween he TINY-2/MICRO-2
and he a ached Compu er erminal device. I is common wi h he frame ground.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 8 -
Da a Carrier De ec (DCD) is an ou pu from he packe con roller. DCD reflec s he s a us of
he CON LED: I is high when a packe connec ion exis s and i is low when no connec ion ex-
is s. This Signal is useful when he packe con roller is used wi h elephone s yle and BBS sof -
ware, since he connec signal, like a modem carrier on he elephone, indica es he presence
of a user.
Da a Terminal Ready (DTR) is an inpu o he TINY-2/MICRO-2 signaling ha he a ached
compu er erminal device is ready o accep da a from he packe con roller. No used on he
TINY-2/MICRO-2.
The able below provides a cross reference o he pinou s of he indus ry s andard 25 pin connec-
or as used on many compu ers and erminals. The TNC-2 and PacComm TNC-200, and rela es
hem o he newer 9 pin connec ors used on many modem compu ers and he TINY-2/MICRO-2.
No e ha connec ing a DTE device o a DCE device using ei her 25 pin connec ors or 9 pin connec-
ors a bo h ends of he cable provides a 's raigh hrough' wiring of pin numbers, i.e. connec col-
umn 1 o column 4 OR connec column 2 o column 3. However, when a 25 pin connec or and 9
pin connec or are used on he same cable, i.e. column 1 o column 3, several pairs of signal lines
mus be crossed.
TINY-2/MICROPO ER-2 RS-232 Serial Port Signal Cross Reference
Conven ional
RS-232
Conven ional
RS-232 DTE DB-25
IBM AT
RS-232 DTE DE-9P
TINY/MICRO
RS-232 DCE DE-9P
TNC-2(00)
RS-232 DC DB-25
Defini ion
Pin
Nr.
Pin
Nr.
Pin
Nr.
Pin
Nr.
FG
TXD
RXD
RTS
CTS
DSR
SG
DCD
Tes
Tes
DTR
RI
1
2
3
4
5
6
7
8
9
10
20
22
shell
3
2
7
8
6
5
1
V+
V-
4
9
5
3
2
7
8
6
5
1
a
-
-
nc
9
b
1
2
3
nc
5
6
7
8
a
+12V
-12V
20
(23)
a
This line goes high when a connec ion exis s
b
RFDCD (Also used for mul i-node NET/ROM and ROSE)

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
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RS-232C Handshaking Protocol
The CTS and RTS lines of he TINY-2/MICRO-2 serial por (labeled P4 on he circui board and RS-
232C on he rear panel) are used by he TINY-2/MICRO-2 firmware for hardware "handshaking" o
con rol he flow of da a be ween he compu er and he packe con roller.
The TINY-2/MICRO-2 always asser s (makes rue) Da a Se Ready (DSR) on P4 pin 6 via a pullup
resis or. Thus, whenever he TINY-2/MICRO-2 is powered up, i signals o he compu er connec ed
o P4 ha he packe con roller is "on line".
The compu er erminal indica es i is ready o receive da a from he TINY-2/MICRO-2 by asser ing
i s Reques To Send (RTS) Signal on P4 pin 4. The packe con roller will send da a when RTS is as-
ser ed (if here is da a o be sen ). If he compu er is no ready o receive da a, i nega es (make
false) RTS o he TINY-2/MICRO-2. Thus, da a flow from he packe con roller o he compu er is
con rolled by he use of he RTS line.
The packe con roller asser s i s Clear To Send (CTS) Ou pu , P4 pin 5, whenever i is ready o re-
ceive da a from he compu er, if he TINY-2/MICRO-2's buffers fill, i will nega e CTS, signaling he
compu er o s op sending da a. The packe con roller will asser CTS when i is again ready o re-
ceive da a from he compu er. Thus, da a flow from he compu er o he packe con roller is regu-
la ed by he use of he CTS line. The CTS line is always oggled, even if "sof ware flow con rol" is
enabled in his direc ion.
If "sof ware flow con rol" is preferred, or if he compu er erminal serial I/O por does no imple-
men CTS/RTS and DTR/DSR handshaking, hen a hree wire cable should be used. If hese RS-
232 con rol lines are no connec ed hey will be pulled up (and hus asser ed) by resis ors a he
TINY-2/MICRO-2 end and proper opera ion will resul . However, a non-s andard serial por may
use some pins for o her purposes, such as supplying power o a peripheral device, so be sure ha
he sys em ei her implemen s he CTS, RTS and DSR handshake or has no connec ions o hese
pins of P4 wha soever. No e ha reference o RS-232C "compa ibili y" or he presence of a DB-25
ype connec or does no guaran ee ha you have a s andard RS-232C serial por !
The PacComm TINY-2/MICRO-2 packe con roller suppor s asynchronous compu er erminal baud
ra es of 300, 1200, 2400, 4800, 9600 and 19,200. The por suppor s s andard pari y op ions as
well as 7- or 8-bi charac er leng hs. Fac ory se ings are 1200 bauds, eigh bi wordleng h, no par-
i y and one s op bi . (UK = 1200, 7, E, 1)
If you wan o in erface he TINY-2/MICRO-2 wi h a device configured as DCE, such as a ele-
phone modem or ano her packe con roller, a so-called "null modem" cable may be cons ruc ed o
in erchange he da a and handshake signals.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
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RADIO INTERFACING
This sec ion describes how o connec he signal cable be ween he TINY-2/MICRO-2 and he ra-
dio. The in erconnec ion should be planned so as o minimize pickup of s ray audio and RF noise
by he lines. You should use shielded wire for all signal-carrying leads.
Read he remainder of his chap er carefully before s ar ing o in erface he packe con roller o
he radio.
Connec he TINY-2/MICRO-2 and radio according o one of he following me hods. Then urn on
he packe con roller and compu er and s ar he compu er communica ions program. Connec he
radio o a dummy load and lis en o he ransmission wi h ano her nearby radio. Se he ransmi
level by he procedure in he Adjus men s Chap er.
You should use shielded wire for all signal-carrying leads. If you no ice a significan hum level in
he moni ored audio, ake measures o remove i . If he ransmi er has an adjus able microphone
gain con rol, ry reducing he sensi ivi y of he ransmi er microphone circui and increasing he
signal level from he TINY-2/MICRO-2 o minimize hum or o her noise problems.
Radio Connector (J2) Pin Definitions
In erfacing he TINY-2/MICRO-2 o a radio involves connec ing he following signals a J2, he five
pin DIN connec or.
Pin 1 - Audio ou pu from he TINY-2/MICRO-2 o he ransmi er.
Pin 2 - Ground for bo h audio and PTT.
Pin 3 - Push- o- alk o allow keying he ransmi er.
Pin 4 - Receive audio from he receiver speaker or auxiliary jack o he TINY-2/MICRO-2.
Pin 5 - Op ional Radio Squelch inpu for RF Carrier De ec ion.
Radio Connec or Viewed from Rear of Packe Con roller
Direct Connection to Microphone and Speaker
The packe con roller was designed o allow hookup and es ing o be done wi hou any modifica-
ions o he radio or any signal level balancing devices in he cables. The direc in erconnec ion
me hod is useful if you devo e he radio exclusively o packe . If you share he radio be ween
packe and voice, you may wan o use he ex ernal in erface me hod below. The packe con rol-
ler's audio signals are fed direc ly in o he microphone connec or or similar auxiliary inpu of he
radio, and he TINY-2/MICRO-2 ou pu is adjus ed o give a proper modula ion level. The receiver
audio is aken from an auxiliary audio ou pu or Speaker jack and fed direc ly o he packe con rol-
ler.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 11 -
Accessory Jack Connection
If he radio has an accessory jack wi h PTT, ransmi audio, and receive audio signals, all connec-
ions be ween he radio and TINY-2/MICRO-2 may be done hrough his jack. The TINY-2/MICRO-
2 is designed o opera e wi h from 10 o 700 millivol audio inpu . This is compa ible wi h he sig-
nal level provided by mos modern ransceivers a he "Fixed Audio Ou pu " connec or on he rear
panel. I is recommended ha a squelched fixed audio ou pu be used if available. If he audio
ou pu is squelched or can be adjus ed o a low enough level o preven false carrier de ec ion, a
direc connec ion o he TINY-2/MICRO-2 audio inpu may be made.
External Interface Box
If you desire o use he radio for bo h packe and voice, and he radio does no have an accessory
jack and you don' wish o add a connec or o he radio, you should cons ruc a separa e in erface
box o permi simul aneous connec ion of he TINY-2/MICRO-2 and a microphone. I may ei her
have i s own speaker or pass he signal hrough o a speaker so ha you can moni or he receive
audio while he packe con roller is hooked up. A schema ic of an ex ernal in erface box is shown
below.
Ex ernal In erface Circui Schema ic

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 12 -
HARD ARE DESCRIPTION
This sec ion includes de ailed hardware specifica ions and a func ional descrip ion of he hardware
design of he TINY-2 and MICROPOWER-2 packe con rollers. Specifica ions apply o bo h packe
con roller models unless specified o herwise. MICROPOWER-2 specifica ions (when differen ) will
be placed in square bracke s [ ]. Firmware specifica ions and opera ing ins ruc ions are con ained
in he Opera ing Manual.
LEDs
PWR The POWER LED is illumina ed whenever he TINY-2/MICRO-2 is connec ed o a power
source and he power swi ch is on.
CON The CONNECT LED illumina es when an AX.25 connec ion exis s on he selec ed s ream for
ha por . (See mul i-connec ion explana ion in Opera ing Manual).
STA The STATUS LED illumina es whenever an AX.25 frame has been sen bu no ye acknowl-
edged. If a connec ion is o be ermina ed (DISCONNECTED) and he STA LED is li , some
frames which were sen bu no acknowledged may be los .
PTT The PTT LED illumina es whenever he TINY-2/MICRO-2 ac iva es he radio keying line.
DCD The DCD LED illumina es when he modem senses a signal.
Detailed Circuit Description
Oscilla or: The crys al, capaci ors and resis ors in he 74HC4060 (U7) circui provide for a s a-
ble clock source for he 4.9152 MHz mas er clock. The 74HC4060 also provides all baud clocks
(X16) and a 600 Hz signal for he real ime clock in errup applied o he SIO (U14) SYNC-B in-
pu .
CPU Complex: The microprocessor (U1) is an NMOS Z-80 (8400-06) [CMOS, 84C00-06]. Bo h
asynchronous serial and HDLC func ions are performed by a Z80 SIO/0 (8440-06) [84C40-06]
(U14). The 27256 [27C256] EPROM (32k by es) (U2) con ains all he firmware, addressed from
0 o 7FFF. The 32k × 8 RAM (U8) holds all buffered da a and ba ery backed parame ers for
he 8400-06 [84C00-06](Z-80) CPU (U1). RAM is addressed from 8000 o FFFF. Each memory
device's chip selec is provided by he 74HC139 decoder (U3), and he RAM chip selec is also
buffered by a power failure de ec ion circui . When vol age is low or removed, he RAM en ers
low power mode, drawing approxima ely one microamp while re aining memory con en s.
Serial Por : SIO (U14) channel B performs asynchronous communica ions hrough ei her a
MAX231 single chip CMOS RS232 ransceiver (U15), or a TTL levels, via an 8-pin connec or
(P3). RS232 signals are in erfaced via an "IBM AT" s yle DE-9P connec or wi h a DCE pinou .
Baud ra es of 300, 1200, 2400, 4800, 9600 and 19.2k are suppor ed.
HDLC: The HDLC func ion is performed by SIO (U14) channel A connec ed o he modem dis-
connec header (J5), and o he on-board in egra ed circui modem. Da a ra es of 300 bauds o
19.2 kilobauds are suppor ed a he header. The SIO HDLC da a signal is conver ed from NRZ
o NRZI in wo logic s ages enrou e o he modem.
Wa chdog Timer: The SIO (U14) RTSA (pin 17) provides he signal ha ul ima ely keys he ra-
dio ransmi er. When he TINY-2/MICRO-2 is ransmi ing, RTSA goes low, which is fed o a
Schmid rigger ga e (U6 pin 9) which urns on he PTT LED and re urns a high signal o he
ga e of a VN10 (FET) ransis or (Q2). This high s a e on he VN10 ga e causes i o conduc o
ground, keying he ransmi er, and s ar s C26 charging hrough R17. If he RTSA Signal re-
mains low more han 60 seconds, C26 reaches he Schmid rigger vol age, causing he ga e
(U6) o urn off he PTT LED and he VN1 0, hus unkeying he ransmi er.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 13 -
Modem: The TCM3105 modem (U16) employs a Bell 202 modula or and demodula or in a sin-
gle CMOS package. The modula or ransmi s ei her 1200 or 2200 Hz depending on he s a e of
he SIO TXD line (U14 pin 14). The modem one ou pu (U16 pin 11) goes hrough a 10k rim-
po o allow ampli ude adjus men o achieve proper ransmi er devia ion.
Since he TCM 3105 always produces ones when powered, here is an audio cu -off circui em-
ployed using a VN10 FET (Q3) and a 2.2k resis or ha swamps mos ransmi audio o ground
when he RTSA line is high (receive). This allows normal voice use of he radio while he TINY-
2/MICRO-2 is connec ed.
The demodula or con ains a swi ched capaci ive fil ering ne work, and is sensi ive o audio lev-
els down o 10 mV. The receive bias adjus men (R9) allows op imizing he bias level for a par-
icular TCM3105 modem IC . Received da a is ou pu on U16 pin 8 and is rou ed hrough he
clock recovery circui before he SIO (U14).
NOTE: The on-board radio modem is only capable of 1200 baud opera ion as ins alled. For
higher (or lower) radio da a ra es, a ach an ex ernal modem o he J5 modem disconnec
header.
Ba ery backed RAM (bbRAM): The en ire 32k of RAM (U8) is backed up wi h a 3 Vol li hium
ba ery. The 74HC132 IC (U3) is also ba ery powered keeping pin 20 (CE) of he RAM disabled
(high) during periods of low power o he TINY-2/MICRO-2 ( ypically 7.5 Vol s and below).
Power Supply: The 7805 regula or (U5) supplies he main por ion of he board wi h clean, s a-
ble 5 Vol power. The incoming posi ive vol age is rou ed hrough a choke (L1) and diode (D6)
for reverse polari y pro ec ion and o he power swi ch. I feeds he 7805 regula or and pin 14
of he MAX231 IC (U15). The MAX231 has in ernal oscilla ors which allow i o genera e a neg-
a ive vol age o suppor he RS232 levels. A vol age approxima ely one Vol below he incoming
supply vol age can normally be measured. The ba ery circui is isola ed by diodes o keep he
RAM and he 74HC132 powered whenever JP-B is ins alled. The TINY-2 requires approxima ely
220 mA a 9 – 14 VDC [MICROPOWER-2 = 40 mA.]
Modem Disconnect - J5
The modem disconnec on he TINY-2/MICRO-2 PC board (J5) is provided for using higher-speed
modems, or more sophis ica ed, higher-performance modems for sa elli e or o her uses. This con-
nec or is he same as he TAPR TNC-2 header.
A physical connec or for J5 is ins alled on he MICROPOWER-2, bu no on all versions of he TINY-
2. Any S andard 20-pin header for use wi h IDC cable connec ors should be sui able for ins alla ion
on he TINY-2. Par s are available from PacComm. When ins alling he connec or, be sure o line
up he marked pin (pin 1 ) of he header wi h he he PC board pin 1 marking.
To use an ex ernal modem, i is necessary o cu he races be ween pins 1-2 and 17-18 on he
bo om of he TINY-2/MICRO-2 PC board wi h a sharp knife or Mo oTool. If RX Clock is provided by
he ex ernal modem, hen cu 13-14. If CTS is provided, cu 9-10.
CAUTION: DO NOT CUT ANY OTHER TRACES WHICH PASS THROUGH THE J5 AREA AND WHICH
ARE NOT TO J5 PINS!
Once he races are cu a J5, you mus ins all push-on jumpers or a shor ing connec or on he
above pin pairs o use he on-board modem. This also applies o he MICROPOWER-2.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 14 -
The signals used a connec or J5 are a s andard TTL in erface levels. A TTL high is grea er han
+2.4 Vol s bu less han +5.25 Vol s. A TTL low is less han 0.4 Vol s bu grea er han 0 Vol s.
DO NOT connec an RS-232C level modem direc ly o J5!
If you elec o use an off-board modem, be sure o properly shield he in erconnec ing cables for
RFI pro ec ion.
J5 Pin Definitions
The following informa ion is primarily for hose who wish o in erface ex ernal modems o he
packe con roller. Familiari y wi h modem and serial da a channel erms is assumed.
Pin 1 Carrier De ec Inpu
This pin ells he SIO radio por ha a valid da a carrier has been de ec ed. I should be
pulled high when no carrier is de ec ed and low when a carrier is presen . I is normally
jumpered o pin 2 when he on-board modem is used.
Pin 2 Carrier De ec Ou pu
This pin is an ou pu from he on-board modem (via an inver er ga e) and provides he
necessary signals required by pin 1 above. I is normally jumpered o pin 1 when he on-
board modem is used.
Pin 3 SIO Special In errup Inpu
This pin is rou ed o he radio por DCD inpu pin on he SIO. This pin is normally jumpered
o pin 4 when he on-board modem is used.
Pin 4 SIO Special In errup Genera or Ou pu
This signal is an ou pu from he on-board modem. I is normally jumpered o pin 3 when
he on-board modem is used.
Pin 5 SIO RTS Ou pu
This signal is used for ransmi er ac iva ion. I ac iva es he PTT pin of he radio connec or
via he wa ch-dog imer. The SIO will pull his ou pu low when he TINY-2/MICRO-2 wan s
o ransmi ; o herwise i will remain high. This pin is normally jumpered o pin 6 when he
on-board modem is used.
Pin 6 Modem RTS Inpu
This Signal is an inpu o he on-board modem. I should be lef high and pulled low only
when ransmission is desired. This pin is normally jumpered o pin 5 when he on-board
modem is used,
Pin 7 CONNECT S a us Ou pu
This pin is an ou pu from he SIO. I is normally low and goes high only when he TINY-
2/MICRO-2 is in a connec ed s a e. I s S a us is reflec ed by he CON LED.
Pin 8 Unacknowledged Packe s Pending S a us Ou pu
This pin is an ou pu from he SIO. I is normally low and goes high only when he TINY-
2/MICRO-2 has unacknowledged packe s in i s ransmi buffer. I s S a us is reflec ed by he
STA LED.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 15 -
Pin 9 SIO CTS Inpu
This pin is an inpu o he SIO. I is high when he a ached modem is no ready o accep
da a, and low when he a ached modem is ready o accep da a. The packe con roller will
no a emp o send da a when his pin is high. This pin is normally jumpered o pin 10
when he on-board modem is used.
Pin 10 Modem CTS Ou pu
This pin is used by he on-board modem o signal he SIO when i is ready o accep da a.
This pin is normally jumpered o pin 9.
Pin 11 Transmi er Clock (16×) Inpu
This pin is ied o he NRZ- o-NRZI Conver er, which expec s a clock signal a 16 imes he
desired radio por da a ra e, e.g. 4800 Hz for 300 bauds. This pin is normally jumpered o
pin 12 when he on-board modem is used.
Pin 12 Transmi er Clock (16×) Ou pu
This pin is ied o he radio baud ra e swi ch ne work. I provides a clock a 16 imes he
desired radio por da a ra e. This pin is normally jumpered o pin 11 when he on-board
modem is used.
Pin 13 Receive Clock Inpu
This pin is ied o he SIO receive clock inpu pin. I expec s a clock a he desired da a ra e
(1200 Hz for 1200 bauds), of he proper phase rela ionship o he received da a, This pin is
normally jumpered o pin 14 when he on-board modem is used.
Pin 14 Receive Clock Ou pu
This pin is he received da a clock signal derived from he NRZI- o-NRZ conver er. This pin
is normally jumpered o pin 13 when he on-board modem is used.
Pin 15 TINY-2/MICRO-2 Ground Reference
This pin ies o he TINY-2/MICRO-2 digi al ground a he SIO.
Pin 16 Addi ional Ground Reference
Pin 17 Receive Da a Inpu
This pin is he received da a inpu o he NRZI- o-NRZ Conver er. This pin is normally jum-
pered o pin 18 when he on-board modem is used.
Pin 18 Receive Da a Ou pu
This pin provides receive da a from he on-board modem. This pin is normally jumpered o
pin 17 when he on-board modem is used.
Pin 19 Transmi Da a Ou pu
This line is he SIO da a ou pu . This pin is normally jumpered o pin 20 when he on-board
modem is used.
Pin 20 Transmi Da a Inpu
This inpu line accep s da a o be be ransmi ed by he modem. This pin is normally jum-
pered o pin 19 when he on-board modem is used.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 16 -
ADJUSTMENTS
Jumper Functions
The following able lis s he func ion of each jumper on he TINY-2/MICRO-2 PC board. The nor-
mal (S andard jumper se ing) posi ions for each are shown.
JP B : Li hium Ba ery
• ON (normal) Li hium ba ery connec ed
• OFF Li hium ba ery disconnec ed
JP D: NET/ROM + RFDCD
• N (normal) NET/ROM inpu o DCDB
• RF RF Squelch o DCDB
JP L: Digi al Loopback
• N (normal) Normal Modem Opera ion
• L Digi al loopback mode
JP RA: Audio Inpu Impedance
• ON (normal) Speaker audio inpu
• OFF High impedance audio inpu
JP Aux: Auxiliaryl/O
• Auxiliary I/O lines for MICROPOWER-2 wi h prin er op ion
JP 8: Power Connec ion
• Auxiliary connec ion poin for 12 V and gnd for accessories
Trimpot/Varicap Adjustments
Mos of he following adjus men s mus be performed wi h he TINY 2/MICRO-2 removed from i s
cabine . Remove he packe con roller from i s cabine by removing bo h fron and rear end pla es
and plas ic bezels. Use cau ion no o damage he grounding s raps a ached o some of he end
pla e screws.
• C17 CPU oscilla or frequency
• R9 Modem bias level
• R12 Transmi ou pu level
• R26 Modem carrier de ec level
Baud Rate Setting
To se he baud ra e on he packe con roller, remove he TINY-2/MICRO-2 from i s cabine . There
are wo se s of jumper headers [DIP swi ches] along he fron edge of he circui board wi h labels
of 3, 12, 24, 48, 96, and 19.2 for bo h TERMINAL and RADIO. These numbers correspond o 300,
1200, 2400, 4800, 9600, or 19,200 baud ra es. Place he jumper on he wo pins [ urn he sec ion
of he DIP swi ch ON] for he desired ra e for bo h he compu er and radio.
WARNING: Place one and only one jumper for he compu er side, and only one on he radio side.
[Only one swi ch on he MICROPOWER-2 should be ON per sec ion.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 17 -
Audio Input Level
The TINY-2/MICRO-2 is designed o opera e wi h from 10 o 700 mV audio inpu . If you ob ain au-
dio from he headphone or ex ernal speaker jack on he radio, place a shor ing block on he pins
of JPR (fac ory defaul ) and adjus he audio level o approxima ely 20 mV wi h he aid of a high
impedance Vol me er or oscilloscope. If no such measuring equipmen is available, se he volume
con rol a a posi ion below ha normally used.
If direc connec ion is made o he radio's discrimina or (demodula or) or any o her high impe-
dance audio source, remove he shor ing block from JP R.
NOTE: The audio level should be se as o as low a value as possible if an unsquelched radio is
used. The TINY-2/MICRO-2 modem will show false DCD indica ions on noise if he audio level is
se oo high.
Transmit Level Setting
Connec he TINY-2/MICRO-2 and radio as shown in he radio in erfacing chap er. Turn on he
packe con roller and compu er and s ar he compu er communica ions program. Connec he ra-
dio o a dummy load and lis en o he ransmission wi h ano her nearby radio. The ou pu level is
se by adjus ing rimpo R12 which is accessible hrough he rear panel opening marked "TTL Com-
pu er."
1. En er he command CAL<CR> and he le er 'K' o cause he TINY-2/MICRO-2 o key he radio
wi h a s eady one. The high or low one is selec ed by pressing he space bar. NOTE: The
wa chdog imer will cause he PTT circui o rese approxima ely one minu e af er he 'K' key is
depressed. If you need a longer adjus men ime, ype 'Q'<CR> o re urn o he command
promp and res ar he procedure.
2. Wi h he TINY-2/MICRO-2 keying he ransmi er and he higher frequency one selec ed, ad-
jus he ransmi audio level rimpo (R12) while observing a service moni or or devia ion me er
uned o he ransmi ing frequency. Se he devia ion for 3 o 3.5 kHz on he higher pi ched
one and check ha he lower one is a leas 2.5 kHz devia ion.
3. If he proper equipmen is no available as described above, make he devia ion adjus men by
urning he adjus men screw on he rimpo un il no increase in ou pu level is heard a he
moni oring receiver. Then ro a e he adjus men screw of he rimpo in he opposi e direc ion
un il he audio signal on he moni oring receiver is sligh ly, bu no iceably, reduced from he
maximum level.
NOTE: I is be er o have oo low han oo high a drive level. A high drive level causes over-
devia ion, unnecessary in erference, and makes your signal less copyable. Lis eners may also
no ice some low-level packe ones when using he radio for voice work.
4. The ransmi er devia ion is now se o approxima ely he correc level. Type he command 'Q'
o unkey he ransmi er.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 18 -
Modem Receive Bias Adjustment
Trimpo (R9 100k) is he modem bias adjus men . The fac ory procedure below is used o adjus
he modem bias. I normally resul s in a value of 2.65 o 2.70 VDC on pin 7 of he TCM3105 mo-
dem chip (U16). The se ing does no seem o drif over ime bu may need o be changed i a dif-
feren modem chip is subs i u ed. If i is necessary o adjus he modem bias, he following proce-
dure should be used.
1. Prepare o perform an audio loopback by jumpering pins 1 and 4 of J2, he radio connec or.
2. Give he commands: CAL<CR>, KD<CR> o provide a 'di hered' ransmi signal for loopback
demodula ion. When he adjus men is comple ed, ype 'Q' o discon inue he one. NOTE: The
wa chdog imer will cause he PTT circui o rese approxima ely one minu e af er he 'KD' Keys
are depressed. If you need a longer adjus men ime, ype 'Q'<CR> o re urn o he cmd:
promp and res ar he procedure.
3. Observe he signal ou pu on pin 8 of he TCM3105 (U16) wi h an oscilloscope. I may be nec-
essary o increase he modem ou pu level by adjus ing rimpo R12 o ge a s rong enough
signal for decoding. The signal should be a square wave. Adjus R26 o cause he posi ive and
nega ive por ions of he square wave o be of equal dura ion.
4. En er Q, remove he jumper from J2 and readjus R12 if needed.
Carrier Detect Level
Trimpo R26 should be adjus ed o cause he DCD LED o illumina e when a weak inpu signal o
he modem is presen and o go ou when no signal is presen . See he sec ion on audio inpu lev-
els.
Crystal Oscillator Adjustment
You may adjus he oscilla or wi h he variable capaci or C17, o wi hin a 5 kHz range ( ypical) from
i s 4.9152 MHz nominal frequency o move a harmonic a few kiloher z off of a favori e opera ing
frequency. The se ing of his frequency is no cri ical. A 30 kHz error a he oscilla or frequency
will resul in only a .6 % error a 1200 baud.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 19 -
TROUBLESHOOTING
WARNING: Never remove or inser an IC wi h power on!
The PacComm packe con roller is a complex piece of elec ronic equipmen . Servicing mus be ap-
proached in a logical manner. The bes prepara ion for roubleshoo ing is o s udy he de ailed
hardware descrip ion above. While i is no possible o presen all possible problems, symp oms
and probable cures, his sec ion of he manual will give direc ion o roubleshoo ing based on our
experience.
Press all socke ed ICs in o heir socke along each edge. If here is any sign of corrosion on any IC
pins, remove each IC, one a a ime, and burnish he pins. Of en simply removing and reins alling
he ICs will cure in ermi en problems caused by vibra ion or humidi y affec ing he IC socke s. In-
spec all solder join s for a smoo h shiny appearance. A dull gray appearance may be an indica ion
of a crys allized solder join . Use a small soldering iron designed for prin ed circui work and re-
solder he connec ion.
Remember ha all he logic circui s opera e a s andard TTL levels (a "low" is less han plus 0.4 V
and a "high" is grea er han plus 2.4 Vol s), and all digi al inpu s and ou pu s swi ch be ween
hese wo levels. Thus, if you see logic signals swi ching be ween 0 and, say, 1 V, you can be sure
here is a problem (usually a shor ). On he o her hand, do no mis ake swi ching ransien s on
digi al logic lines for improper opera ion - hese show up as ringing and o her dis or ions.
Verify ha here is ac ivi y on he con rol bus READ and WRITE lines, he CHIP ENABLE lines on
he memories (U2 and U8 pins 20), he IOREQ line on CPU (U1) pin 20 and he INT line on CPU
(U1) pin 16. Each of hese lines should show ac ivi y, and if any line is quie his is a sign of rou-
ble. Address and da a line problems may also show up as lack of ac ivi y on he con rol bus lines,
especially he chip selec s. Check each of he 16 address and 8 da a lines for ac ivi y. Any lines
showing a lack of ac ivi y are no opera ing properly.
If you suspec problems wi h address or da a lines, ry removing all he memory chips. Each ad-
dress and da a line will now show a dis inc pa ern. The address lines should be (possibly dis or -
ed) square waves whose periods increase by a fac or of wo on successive lines as you s ep line by
line from A0 o A15.
Logic lines ha show no ac ivi y may of en be raced o a shor on he pc board, probably due o a
defec ive solder join . Follow he ins ruc ions above for inspec ing solder join s. If you decide o
use an Ohmme er o check for shor ed lines, use a low vol age/low curren es ins rumen . (Mos
modem DVMs are fine for his.) If in doub , remove any ICs connec ed o he lines you are measur-
ing. If you suspec a shor , check he high densi y areas of he PC board for he problem. In mos
cases he shor will be found here.
If an oscilloscope is no available, hen a Vol me er can help you find serious difficul y on digi al
signal and address lines. Se he me er for he scale where a full 5 Vol s can be displayed. A read-
ing of 1.5 o 3.5 vol s indica es some varying digi al signal. A reading of over 3.5 V or under 1.5 V
is mos likely an indica ion of rouble. A very low, or very high vol age reading is a sign of no ac iv-
i y, or open and shor ed circui s. If you canno pinpoin he rouble using his se of guidelines,
hen you mus ei her ob ain an oscilloscope, or send he board back o PacComm for repair.
If you have an oscilloscope available, he rouble shoo ing is much easier! The checks made above
s ill apply, bu now you can "see" rouble on he oscilloscope waveforms. If you see a 's air-s ep-
ped' waveform on wo differen pins, hen i is likely hey are shor ed oge her. Also, square waves
of half ampli ude, or lines wi h no ac ivi y are dead giveaways on he scope. The scope also allows
you o race he analog sec ions of he device, including he modem.

TINY-2/MICRO-2 Technical Ref., 2. Ed 1989
- 20 -
Be very careful abou shor ing pins on ICs when applying me er or scope probes o he board. I is
a good idea o a ach a secure ground lead o he me er or scope, one ha won' acciden ally
shor across componen s on he board. A good place o pick up his ground is on he ground bus
ha comple ely encircles he perime er of he board. Avoid connec ing in he area where power
leads run o and from he power swi ch o avoid he possibili y of a shor .
Loopback testing
Loopback es ing consis s of having he ransmi sec ion of he packe con roller communica e wi h
he receive sec ion. If his procedure is successful, he correc opera ion of bo h ransmi and re-
ceive sec ions can be verified. If da a is no successfully passed, clues o he malfunc ion may be
ob ained.
There are wo ypes of loopback es ing, analog and digi al. For bo h ypes of es , he command
FULLDUP mus be ON and some ype of connec ion mus be made be ween he ransmi ou pu
and he receive inpu . Once he proper arrangemen s are made, es ing consis s of a emp ing o
pass informa ion from he ransmi sec ion o he receive sec ion of he packe con roller. One
me hod is o send da a o and from he PMS (if he PMS op ion is ins alled) by connec ing o MYP-
CALL. You may also connec o MYCALL and send and receive from he erminal, or send UI frames
and moni or hem. Be sure o undo all he loopback s eps once he es ing is comple ed.
Analog loopback
Remove JPR o place he inpu circui in a high impedance s a e. Ins all a homemade jumper be-
ween pins 1 and 4 of he radio connec or J2. Send UI frames and moni or for heir recep ion or
ry a connec ion as described above. The ou pu level rimpo R12 may have o be urned o near
maximum o allow he modem o hear i self. Failure of he analog loopback es does no necessa-
rily mean here is a modem problem since he ransmi circui s and receive circui s are no op i-
mized for direc connec ion.
Digital loopback
Move he JP L jumper o 'LOOP' and a emp o pass UI frames or connec . Digi al loopback is very
reliable and should work every ime if here is no problem in he digi al por ion of he board.
General Tests
The TINY-2/MICRO-2 has s a us LEDs which are powerful ools in roubleshoo ing. Many suspec ed
problems may be disproved by he following simple es s. Connec a power source o he TINY-
2/MICRO-2 and a Vol me er (15 Vol scale) o pin 2 of he RS-232 connec or. Do no connec any
compu er or radio cables. Turn on he TINY-2/MICRO-2. Observe he LEDs. If he TINY-2/MICRO-2
powers up wi h he PWR, CON and STA LEDs li , followed by he CON and STA LEDs ex inguishing
a second or so la er, and he Vol me er shows a lo of ac ivi y for abou ½ second, he TINY-2/
MICRO-2 digi al sec ion is opera ing and a emp ing o send a sign on message ou he serial por .
Step 1: Obvious Problems
Look for any unusual physical symp oms. Is he uni drawing excessive curren ? Are any compo-
nen s discolored? Does some hing smell burn ? Do any of he par s seems excessively warm? In
general, heir normal empera ure (NMOS) will be qui e warm o he ouch. CMOS par s should no
show any hea ing.