Occasionally, you have to push hard (and wiggle) the connector to get it in to fully seat into the radio. This is to keep a water resistant seal between the connector and the radio case to keep water from getting into the connector on the radio. If the connector isn't fully seated, you are only able to hear and not transmit. Motorola 2 prong M1/ GP300 - 2 Prong Plug with 2.5mm and 3.5mm plugs with 8mm spacing:
XTN Series: XTN446, XTN500, XTN600
XTN XV Series: XV1100, XV2100, XV2600, XV4100
XTN XU Series: XU1100, XU2100, XU2600, XU4100
XTN AX Series: AXV5100, AXU4100
CLS Series: CLS1110, CLS1413, CLS1450, CLS1450C,
CLS1450CB
Motorola Spirit Series: SV10, SV11, SV11D, SV21, SV12, SV22,
SV22C, SU210, SU22, SU22C, SU220 VHF / UHF Spirit, Spirit Pro, Spirit Pro+,
Spirit HP 10
Spirit MU Series: MU11, MU11C, MU11CV, MU12, MU12C, MU12CV,
MU21C, MU21CV, MU22CVS, MU24CV, MU24CVS, MU24CVST
Spirit MV Series: MV11, MV11C, MV11CV, MV12, MV12CV, MV21C,
MV21CV, MV22CV, MV24CVS
CP Series: CP88, CP040. CP100, CP110, CP125, CP150,
CP200, CP250, CP300
GP Series: GP2000 , GP2100, GP300, GP308, GP68,
GP88, GP88S
SP Series: SP10, SP21, SP50+, SP50
CT Series: CT150, CT250, CT450, CT450LS
PRO Series: PRO1150, PRO2150, PRO3150
P Series: P040, P080, P1225, P1225LS
DTR Series: DTR410, DTR550, DTR610, DTR650
Other Series: GTI, GTX, LTS2000, VL130, PMR446, ECP100,
Mag One BPR400, EP450, AU1200, AV1200
RDX Series: RDV-5100, RDV2020, RDU2020, RDU2080DD,
RDU4100, RDU4160D, RDV2080D, RDV5100
FDC: FD-150A,
FD-450A, FD-160A, FD-460A
Blackbox Series: Blackbox-V, Blackbox-U (M1 Connector)