GP300 CPS is for new GP320/340/460....
Old GP300 still program by RSS,Which run in DOS.

they are on the middle left of the board.
they are in metal mantle with eyelet.
L253 is TX VCO
L258 is RX VCO

Many GP300UL/UH/GP88/P110 can work at HAM BAND 430-440MHz, it has about 40-50MHz range for VCO. There is two VCO adjustments on the board, we can adjust it with out software. One is for RX, one is for TX. If you set the frequency far away from the standard frequency, you need adjust the VCO.

There is not all MTX838 radios can be easliy change to B7 model (with full keypad and LCD) by program by LAB RSS,some radio need change the logic board or rewrite EEPROM(28C256) .

So you must save the codeplug date by lab RSS. If you can¡¯t update your radio you will need it.

You can buy BNC to RF Adapter for GP300/350, Part number is HLN9756A.

The third part adapter is much cheaper the M¡¯s.

First you can use a SMART NET/ZONE Decode software to get a valid ¡°individual ID¡±. I think you have already get system ID and talk group number and control frequency

You also can reckon some valid ¡°individual ID¡± which is not often used.

When you program the radio not use SMARTZONE, use ...

You can use MTX lab rss to read a radio which has full keypad with LCD. then you can program to your radio. JUST is it.

But you will change your radio's model number and S/N.

It'S "MICROPHONE, SPEAKER, REMOTE",about $124-$168.

there is no product for accessories, which is in common use at M's site. Perhaps you can download PDF prouducts to know it more.

http://www.accesspointcd.com/catalog.html

use your RJ11(12) 4PIN to connect to GM300
They are audio line.