In which table TransType (transaction type) is stored ?

TransType value is stored in ObjectType column of according table. And there is no any special table with TransType values and descriptions.
It could help you (not sure it's up-to-date):code NOB -1 - Not an Object
GNR 0 - General Object
ACT 1 - Accounts
CRD 2 - Cards
DSC 3 - Discount Codes
ITM 4 - Items
VTG 5 - Vat groups
PLN 6 - Price List Names
SPP 7 - Special Prices
ITG 8 - Item Groups
RTM 9 - Rates matching
CRG 10 - Card payment groups
CPR 11 - Contact persons
USR 12 - Users
INV 13 - Invoices
RIN 14 - Revert Invoices
DLN 15 - Delivery Notes
RDN 16 - Revert Delivery Notes
RDR 17 - Orders
PCH 18 - Purchases
RPC 19 - Revert Purchases
PDN 20 - Purchase Delivery Notes
RPD 21 - Revert Purchase Delivery Notes
POR 22 - Purchase Orders
QUT 23 - Quotations
RCT 24 - Receipts
DPS 25 - Deposits
MTH 26 - Match History
CHH 27 - Checks History
BTF 28 - Journal Batches
BTD 29 - Journal Batches Directory
JDT 30 - Journal Transactions
ITW 31 - Item - Warehouse accumulators
ADP 32 - Printing Administration
CLG 33 - Contact Log
RCR 34 - Recurring Transactions
NNM 35 - Objects Next Serial Number
CRC 36 - Credit Cards
CRN 37 - Currency Codes
IDX 38 - Index (Madad)
ADM 39 - Administration
CTG 40 - Credit Terms
PRF 41 - Form Preferences
BNK 42 - Bank pages
MRC 43 - Firm groups (Marca)
CQG 44 - Card query groups
TRC 45 - Ttansaction codes
VPM 46 - Payment to vendor
SRL 47 - Serial numbers
ALC 48 - Import expenses
SHP 49 - Shipment types
LGT 50 - Length units
WGT 51 - Weight units
ITB 52 - Item groups
SLP 53 - Sales person
FLT 54 - Reports filter
TRT 55 - Transaction types
ARG 56 - Arancel (custom) groups
CHO 57 - Checks paid to vendors (Outgoing checks)
INM 58 - Inventory match
IGN 59 - Inventory General Entry
IGE 60 - Inventory General Exit
PRC 61 - Profit Center
OCR 62 - Overhead cost rate
PRJ 63 - Project
WHS 64 - Warehouses Codes & Names
COG 65 - Commission groups
ITT 66 - Item Tree links
WTR 67 - Warehouses Transfers
WKO 68 - Work Orders
IPF 69 - Import file
CRP 70 - Credit pay systems
CDT 71 - Credit Due Terms
CRH 72 - Credit History
SCN 73 - Substitutional catalog num
CRV 74 - Credit Payments
RTT 75 - Index & currency rates
DPT 76 - Deposit Temporary
BGT 77 - Budget
BGD 78 - Budget _STR_system
RCN 79 - Retailer chains
ALT 80 - Alert templates
ALR 81 - Alerts pool
AIB 82 - Alerts In box
AOB 83 - Alerts Out box
CLS 84 - Contact log subjects
SPG 85 - Special prices for groups
SPRG 86 - Run externals applications
MLS 87 - Mailing lists
ENT 88 - Panama - enterada
SAL 89 - Panama - salida
TRA 90 - Panama - traspaso
BGS 91 - Budget Scenario
IRT 92 - Interest Rates
UDG 93 - User defaults groups
SRI 94 - Items serial numbers
FRT 95 - Finance Reports Template
FRC 96 - Finance Reports Categories
OPR 97 -
OIN 98 -
OIR 99 -
OSR 100 -
OST 101 -
OFR 102 -
CLT 103 - Contact log types
CLO 104 - Contact log locations
ISR 105 - Internet Service Request
IBT 106 - Item batch numbers
ALI 107 - Alternative Items
PRT 108 - Partners
CMT 109 - Competitors
UVV 110 - User valid values
FPR 111 - Finance period
DRF 112 - Document draft
SRD 113 - Internal manage of SRI and IBT
UDC 114 - User display categories
PVL 115 - Pelecard Vendors List
DDT 116 - Deduction at source - Terraces
DDG 117 - Deduction at source - Groups
UBR 118 - Users - Branch
UDP 119 - Users - Departments
WST 120 - Workflow - Steps
WTM 121 - Workflow - Templates
WDD 122 - Workflow - Documants
CHD 123 - Check out drafts
CINF 124 - Company info
EXD 125 - Expenses definition
STA 126 - Sales Tax Authorities
STT 127 - Sales Tax Authorities Type
STC 128 - Sales Tax Code
CRY 129 - Countries
CST 130 - States
ADF 131 - Address format
CIN 132 - Correction Invoice
CDC 133 -Cash Discount
QCN 134 - User Querry Category Names
IND 135 -VAT Indicator EC
DMW 136 -Data Migrate Wizard Pacages
CSTN 137 -Station Id
IDC 138 - Indicator
GSP 139 - Goods Shipment
PDF 140 -payment draft
QWZ 141 - Query Wizard
ASG 142 - Account Segmantation
ASC 143 - Account Segmantation Categories
LCT 144 - Location
TNN 145 - 1099
CYC 146 - Cycle
PYM 147 - Payment Method
TOB 148 - 1099 Begining Balances
RIT 149 - Dunning Interest Rate
BPP 150 - BP Priorities
DUN 151 -
UFD 152 - User Fields - Descr.
UTB 153 - User Tables
CUMI 154 - User Menu
PYD 155 - Payment run
PKL 156 -
PWZ 157 - Payment Wizard
PEX 158 - Payment Results Table
PYB 159 - Payment Block
UQR 160 - Queries
CBI 161 - Central bank ind
MRV 162 - Material revaluation was: SST
CPI 163 - Correction A/P Invoice was: SLT
CPV 164 - Correction A/P Invoice Reversal was: CTR
CSI 165 - Correction A/R Invoice was: SCL
CSV 166 - Correction A/R Invoice Reversal was: SCO
SCS 167 - Service Call Status
SCT 168 - Service Call Type
SCP 169 - Service Call Problem Type
CTT 170 - Contract Template
HEM 171 - Employees
HTY 172 - Employee Types
HST 173 - Employee Status
HTR 174 - Termination reason
HED 175 - Education Types
INS 176 - Install Base
AGP 177 - Agent Person
WHT 178 - Withholding Tax
RFL 179 - 347, 349 and WT reports previously displayed
VTR 180 -
BOE 181 - Boe for Payment
BOT 182 - Bill Of Exchang Transaction
FRM 183 - File Format
PID 184 - Period Indicator
DOR 185 - Doubtful Receivables
HLD 186 - Holiday Table
CRB 187 - Bessiness Partner - Bank accounts
SST 188 - Service Call Solution Status was: 162
SLT 189 - Service Call Solutions was: 163
CTR 190 - Service Contracts was: 164
SCL 191 - Service Call was: 165
SCO 192 - Service call origin was: 166
UKD 193 - User Keys Descr
TSI 280 - A/R Tax Invoice
TPI 281 - A/P Tax Invoice
TXD 282 - A/R Tax Invoice - Drafts
CCD 283 - Cargo Customs Declaration was: 196[/code]HT